| Message ID | 1640342548-4520-1-git-send-email-akash.hadke@kpit.com |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [poky,dunfell] glibc: Add fix for data races in pthread_create and TLS access | expand |
On Fri, Dec 24, 2021 at 12:42 AM akash hadke via lists.openembedded.org <akash.hadke=kpit.com@lists.openembedded.org> wrote: > > Inconsistency detected by ld.so: dl-tls.c: 493: _dl_allocate_tls_init: Assertion `listp->slotinfo[cnt].gen <= _rtld_local._dl_tls_generation' failed! > caused by dlopen (in _dl_add_to_slotinfo and in dl_open_worker) doing > listp->slotinfo[idx].gen = GL(dl_tls_generation) + 1; > //... > if (any_tls && __builtin_expect (++GL(dl_tls_generation) == 0, 0)) > while pthread_create (in _dl_allocate_tls_init) concurrently doing > assert (listp->slotinfo[cnt].gen <= GL(dl_tls_generation)); > > Backported below patch that can fix the following bugs with a lock > that prevents DTV setup running concurrently with dlopen or dlclose. > > Bug 19329: https://sourceware.org/bugzilla/show_bug.cgi?id=19329 > Bug 27111: https://sourceware.org/bugzilla/show_bug.cgi?id=27111 > > Patch: 0031-elf-Fix-data-races-in-pthread_create-and-TLS-access-BZ-19329.patch > Link: https://sourceware.org/git/?p=glibc.git;a=patch;h=1387ad6225c2222f027790e3f460e31aa5dd2c54 > > It requires a supporting patch > 0030-elf-Refactor_dl_update-slotinfo-to-avoid-use-after-free.patch > Link: https://sourceware.org/git/?p=glibc.git;a=patch;h=c0669ae1a629e16b536bf11cdd0865e0dbcf4bee > > After adding the above fix there is a number of racy read accesses > to globals that will be changed to relaxed MO atomics in follow-up > patch given below. > > This fixes the regressions and avoids cluttering the main part > of the fix. > > 0032-elf-Use-relaxed-atomics-for-racy-accesses-BZ-19329.patch > Link: https://sourceware.org/git/?p=glibc.git;a=patch;h=f4f8f4d4e0f92488431b268c8cd9555730b9afe9 > > Backported the below patch to add the test to check the added fix. > 0033-elf-Add-test-case-for-BZ-19329.patch > Link: https://sourceware.org/git/?p=glibc.git;a=patch;h=9d0e30329c23b5ad736fda3f174208c25970dbce > > Previously modids were never resused for a > different module, but after dlopen failure all gaps are reused > not just the ones caused by the unfinished dlopened. > > The code has to handle reused modids already which seems to > work, however the data races at thread creation and tls access > (see bug 19329 and bug 27111) may be more severe if slots are > reused. Fixing the races are not simpler if reuse is disallowed > and reuse has other benefits so upstream added fix > https://sourceware.org/git/?p=glibc.git;a=commit;h=572bd547d57a39b6cf0ea072545dc4048921f4c3 > for the following bug. > > Bug 27135: https://sourceware.org/bugzilla/show_bug.cgi?id=27135 > > But in glibc upstream the commit 572bd547d57a was reverted as the > issue with 572bd547d57a patch was the DTV entry only updated on > dl_open_worker() with the update_tls_slotinfo() call after all > dependencies are being processed by _dl_map_object_deps(). However > _dl_map_object_deps() itself might call _dl_next_tls_modid(), > and since the _dl_tls_dtv_slotinfo_list::map was not yet set the > entry can be wrongly reused. > > So added below patch to fix Bug 27135. > 0034-elf-Fix-DTV-gap-reuse-logic-BZ-27135.patch > Link: https://sourceware.org/git/?p=glibc.git;a=patch;h=ba33937be210da5d07f7f01709323743f66011ce > > Not all TLS access related data races got fixed by adding > 0031-elf-Fix-data-races-in-pthread_create-and-TLS-access-BZ-19329.patch, > there are additional races at lazy tlsdesc relocations. > Bug 27137: https://sourceware.org/bugzilla/show_bug.cgi?id=27137 > > Backported below patches to fix this issue. > > 0035-x86_64-Avoid-lazy-relocation-of-tlsdesc-BZ-27137.patch > Link: https://sourceware.org/git/?p=glibc.git;a=patch;h=8f7e09f4dbdb5c815a18b8285fbc5d5d7bc17d86 > > 0036-i386-Avoid-lazy-relocation-of-tlsdesc-BZ-27137.patch > Link: https://sourceware.org/git/?p=glibc.git;a=patch;h=ddcacd91cc10ff92d6201eda87047d029c14158d > > The fix 0031-elf-Fix-data-races-in-pthread_create-and-TLS-access-BZ-19329.patch > for bug 19329 caused a regression such that pthread_create can > deadlock when concurrent ctors from dlopen are waiting for it > to finish. > Bug 28357: https://sourceware.org/bugzilla/show_bug.cgi?id=28357 > > Backported below patch to fix this issue. > 0037-Avoid-deadlock-between-pthread_create-and-ctors.patch > Link: https://sourceware.org/git/?p=glibc.git;a=patch;h=024a7640ab9ecea80e527f4e4d7f7a1868e952c5 > > Signed-off-by: Akash Hadke <akash.hadke@kpit.com> > Signed-off-by: Akash Hadke <hadkeakash4@gmail.com> This is a quite extensive change set. I'd like to get Khem's opinion as glibc maintainer. Thoughts, Khem? Steve > --- > ...l_update-slotinfo-to-avoid-use-after-free.patch | 66 +++++ > ...in-pthread_create-and-TLS-access-BZ-19329.patch | 191 ++++++++++++++ > ...elaxed-atomics-for-racy-accesses-BZ-19329.patch | 206 +++++++++++++++ > .../0033-elf-Add-test-case-for-BZ-19329.patch | 144 +++++++++++ > ...0034-elf-Fix-DTV-gap-reuse-logic-BZ-27135.patch | 180 ++++++++++++++ > ...Avoid-lazy-relocation-of-tlsdesc-BZ-27137.patch | 56 +++++ > ...Avoid-lazy-relocation-of-tlsdesc-BZ-27137.patch | 124 +++++++++ > ...deadlock-between-pthread_create-and-ctors.patch | 276 +++++++++++++++++++++ > meta/recipes-core/glibc/glibc_2.31.bb | 8 + > 9 files changed, 1251 insertions(+) > create mode 100644 meta/recipes-core/glibc/glibc/0030-elf-Refactor_dl_update-slotinfo-to-avoid-use-after-free.patch > create mode 100644 meta/recipes-core/glibc/glibc/0031-elf-Fix-data-races-in-pthread_create-and-TLS-access-BZ-19329.patch > create mode 100644 meta/recipes-core/glibc/glibc/0032-elf-Use-relaxed-atomics-for-racy-accesses-BZ-19329.patch > create mode 100644 meta/recipes-core/glibc/glibc/0033-elf-Add-test-case-for-BZ-19329.patch > create mode 100644 meta/recipes-core/glibc/glibc/0034-elf-Fix-DTV-gap-reuse-logic-BZ-27135.patch > create mode 100644 meta/recipes-core/glibc/glibc/0035-x86_64-Avoid-lazy-relocation-of-tlsdesc-BZ-27137.patch > create mode 100644 meta/recipes-core/glibc/glibc/0036-i386-Avoid-lazy-relocation-of-tlsdesc-BZ-27137.patch > create mode 100644 meta/recipes-core/glibc/glibc/0037-Avoid-deadlock-between-pthread_create-and-ctors.patch > > diff --git a/meta/recipes-core/glibc/glibc/0030-elf-Refactor_dl_update-slotinfo-to-avoid-use-after-free.patch b/meta/recipes-core/glibc/glibc/0030-elf-Refactor_dl_update-slotinfo-to-avoid-use-after-free.patch > new file mode 100644 > index 0000000..dba491f > --- /dev/null > +++ b/meta/recipes-core/glibc/glibc/0030-elf-Refactor_dl_update-slotinfo-to-avoid-use-after-free.patch > @@ -0,0 +1,66 @@ > +From c0669ae1a629e16b536bf11cdd0865e0dbcf4bee Mon Sep 17 00:00:00 2001 > +From: Szabolcs Nagy <szabolcs.nagy@arm.com> > +Date: Wed, 30 Dec 2020 21:52:38 +0000 > +Subject: [PATCH] elf: Refactor _dl_update_slotinfo to avoid use after free > + > +map is not valid to access here because it can be freed by a concurrent > +dlclose: during tls access (via __tls_get_addr) _dl_update_slotinfo is > +called without holding dlopen locks. So don't check the modid of map. > + > +The map == 0 and map != 0 code paths can be shared (avoiding the dtv > +resize in case of map == 0 is just an optimization: larger dtv than > +necessary would be fine too). > + > +Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> > +--- > + elf/dl-tls.c | 21 +++++---------------- > + 1 file changed, 5 insertions(+), 16 deletions(-) > +--- > +Upstream-Status: Backport [https://sourceware.org/git/?p=glibc.git;a=patch;h=c0669ae1a629e16b536bf11cdd0865e0dbcf4bee] > +Signed-off-by: Akash Hadke <akash.hadke@kpit.com> > +Signed-off-by: Akash Hadke <hadkeakash4@gmail.com> > +--- > +diff --git a/elf/dl-tls.c b/elf/dl-tls.c > +index 24d00c14ef..f8b32b3ecb 100644 > +--- a/elf/dl-tls.c > ++++ b/elf/dl-tls.c > +@@ -743,6 +743,8 @@ _dl_update_slotinfo (unsigned long int req_modid) > + { > + for (size_t cnt = total == 0 ? 1 : 0; cnt < listp->len; ++cnt) > + { > ++ size_t modid = total + cnt; > ++ > + size_t gen = listp->slotinfo[cnt].gen; > + > + if (gen > new_gen) > +@@ -758,25 +760,12 @@ _dl_update_slotinfo (unsigned long int req_modid) > + > + /* If there is no map this means the entry is empty. */ > + struct link_map *map = listp->slotinfo[cnt].map; > +- if (map == NULL) > +- { > +- if (dtv[-1].counter >= total + cnt) > +- { > +- /* If this modid was used at some point the memory > +- might still be allocated. */ > +- free (dtv[total + cnt].pointer.to_free); > +- dtv[total + cnt].pointer.val = TLS_DTV_UNALLOCATED; > +- dtv[total + cnt].pointer.to_free = NULL; > +- } > +- > +- continue; > +- } > +- > + /* Check whether the current dtv array is large enough. */ > +- size_t modid = map->l_tls_modid; > +- assert (total + cnt == modid); > + if (dtv[-1].counter < modid) > + { > ++ if (map == NULL) > ++ continue; > ++ > + /* Resize the dtv. */ > + dtv = _dl_resize_dtv (dtv); > + > +-- > +2.27.0 > diff --git a/meta/recipes-core/glibc/glibc/0031-elf-Fix-data-races-in-pthread_create-and-TLS-access-BZ-19329.patch b/meta/recipes-core/glibc/glibc/0031-elf-Fix-data-races-in-pthread_create-and-TLS-access-BZ-19329.patch > new file mode 100644 > index 0000000..25beee1 > --- /dev/null > +++ b/meta/recipes-core/glibc/glibc/0031-elf-Fix-data-races-in-pthread_create-and-TLS-access-BZ-19329.patch > @@ -0,0 +1,191 @@ > +From 1387ad6225c2222f027790e3f460e31aa5dd2c54 Mon Sep 17 00:00:00 2001 > +From: Szabolcs Nagy <szabolcs.nagy@arm.com> > +Date: Wed, 30 Dec 2020 19:19:37 +0000 > +Subject: [PATCH] elf: Fix data races in pthread_create and TLS access [BZ > + #19329] > + > +DTV setup at thread creation (_dl_allocate_tls_init) is changed > +to take the dlopen lock, GL(dl_load_lock). Avoiding data races > +here without locks would require design changes: the map that is > +accessed for static TLS initialization here may be concurrently > +freed by dlclose. That use after free may be solved by only > +locking around static TLS setup or by ensuring dlclose does not > +free modules with static TLS, however currently every link map > +with TLS has to be accessed at least to see if it needs static > +TLS. And even if that's solved, still a lot of atomics would be > +needed to synchronize DTV related globals without a lock. So fix > +both bug 19329 and bug 27111 with a lock that prevents DTV setup > +running concurrently with dlopen or dlclose. > + > +_dl_update_slotinfo at TLS access still does not use any locks > +so CONCURRENCY NOTES are added to explain the synchronization. > +The early exit from the slotinfo walk when max_modid is reached > +is not strictly necessary, but does not hurt either. > + > +An incorrect acquire load was removed from _dl_resize_dtv: it > +did not synchronize with any release store or fence and > +synchronization is now handled separately at thread creation > +and TLS access time. > + > +There are still a number of racy read accesses to globals that > +will be changed to relaxed MO atomics in a followup patch. This > +should not introduce regressions compared to existing behaviour > +and avoid cluttering the main part of the fix. > + > +Not all TLS access related data races got fixed here: there are > +additional races at lazy tlsdesc relocations see bug 27137. > + > +Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> > +--- > + elf/dl-tls.c | 63 +++++++++++++++++++++++++++++++++++++++------------- > + 1 file changed, 47 insertions(+), 16 deletions(-) > +--- > +Upstream-Status: Backport [https://sourceware.org/git/?p=glibc.git;a=patch;h=1387ad6225c2222f027790e3f460e31aa5dd2c54] > +Signed-off-by: Akash Hadke <akash.hadke@kpit.com> > +Signed-off-by: Akash Hadke <hadkeakash4@gmail.com> > +--- > +diff --git a/elf/dl-tls.c b/elf/dl-tls.c > +index 6baff0c1ea..94f3cdbae0 100644 > +--- a/elf/dl-tls.c > ++++ b/elf/dl-tls.c > +@@ -475,14 +475,11 @@ extern dtv_t _dl_static_dtv[]; > + #endif > + > + static dtv_t * > +-_dl_resize_dtv (dtv_t *dtv) > ++_dl_resize_dtv (dtv_t *dtv, size_t max_modid) > + { > + /* Resize the dtv. */ > + dtv_t *newp; > +- /* Load GL(dl_tls_max_dtv_idx) atomically since it may be written to by > +- other threads concurrently. */ > +- size_t newsize > +- = atomic_load_acquire (&GL(dl_tls_max_dtv_idx)) + DTV_SURPLUS; > ++ size_t newsize = max_modid + DTV_SURPLUS; > + size_t oldsize = dtv[-1].counter; > + > + if (dtv == GL(dl_initial_dtv)) > +@@ -528,11 +525,14 @@ _dl_allocate_tls_init (void *result) > + size_t total = 0; > + size_t maxgen = 0; > + > ++ /* Protects global dynamic TLS related state. */ > ++ __rtld_lock_lock_recursive (GL(dl_load_lock)); > ++ > + /* Check if the current dtv is big enough. */ > + if (dtv[-1].counter < GL(dl_tls_max_dtv_idx)) > + { > + /* Resize the dtv. */ > +- dtv = _dl_resize_dtv (dtv); > ++ dtv = _dl_resize_dtv (dtv, GL(dl_tls_max_dtv_idx)); > + > + /* Install this new dtv in the thread data structures. */ > + INSTALL_DTV (result, &dtv[-1]); > +@@ -600,6 +600,7 @@ _dl_allocate_tls_init (void *result) > + listp = listp->next; > + assert (listp != NULL); > + } > ++ __rtld_lock_unlock_recursive (GL(dl_load_lock)); > + > + /* The DTV version is up-to-date now. */ > + dtv[0].counter = maxgen; > +@@ -734,12 +735,29 @@ _dl_update_slotinfo (unsigned long int req_modid) > + > + if (dtv[0].counter < listp->slotinfo[idx].gen) > + { > +- /* The generation counter for the slot is higher than what the > +- current dtv implements. We have to update the whole dtv but > +- only those entries with a generation counter <= the one for > +- the entry we need. */ > ++ /* CONCURRENCY NOTES: > ++ > ++ Here the dtv needs to be updated to new_gen generation count. > ++ > ++ This code may be called during TLS access when GL(dl_load_lock) > ++ is not held. In that case the user code has to synchronize with > ++ dlopen and dlclose calls of relevant modules. A module m is > ++ relevant if the generation of m <= new_gen and dlclose of m is > ++ synchronized: a memory access here happens after the dlopen and > ++ before the dlclose of relevant modules. The dtv entries for > ++ relevant modules need to be updated, other entries can be > ++ arbitrary. > ++ > ++ This e.g. means that the first part of the slotinfo list can be > ++ accessed race free, but the tail may be concurrently extended. > ++ Similarly relevant slotinfo entries can be read race free, but > ++ other entries are racy. However updating a non-relevant dtv > ++ entry does not affect correctness. For a relevant module m, > ++ max_modid >= modid of m. */ > + size_t new_gen = listp->slotinfo[idx].gen; > + size_t total = 0; > ++ size_t max_modid = atomic_load_relaxed (&GL(dl_tls_max_dtv_idx)); > ++ assert (max_modid >= req_modid); > + > + /* We have to look through the entire dtv slotinfo list. */ > + listp = GL(dl_tls_dtv_slotinfo_list); > +@@ -749,12 +767,14 @@ _dl_update_slotinfo (unsigned long int req_modid) > + { > + size_t modid = total + cnt; > + > ++ /* Later entries are not relevant. */ > ++ if (modid > max_modid) > ++ break; > ++ > + size_t gen = listp->slotinfo[cnt].gen; > + > + if (gen > new_gen) > +- /* This is a slot for a generation younger than the > +- one we are handling now. It might be incompletely > +- set up so ignore it. */ > ++ /* Not relevant. */ > + continue; > + > + /* If the entry is older than the current dtv layout we > +@@ -771,7 +791,7 @@ _dl_update_slotinfo (unsigned long int req_modid) > + continue; > + > + /* Resize the dtv. */ > +- dtv = _dl_resize_dtv (dtv); > ++ dtv = _dl_resize_dtv (dtv, max_modid); > + > + assert (modid <= dtv[-1].counter); > + > +@@ -793,8 +813,17 @@ _dl_update_slotinfo (unsigned long int req_modid) > + } > + > + total += listp->len; > ++ if (total > max_modid) > ++ break; > ++ > ++ /* Synchronize with _dl_add_to_slotinfo. Ideally this would > ++ be consume MO since we only need to order the accesses to > ++ the next node after the read of the address and on most > ++ hardware (other than alpha) a normal load would do that > ++ because of the address dependency. */ > ++ listp = atomic_load_acquire (&listp->next); > + } > +- while ((listp = listp->next) != NULL); > ++ while (listp != NULL); > + > + /* This will be the new maximum generation counter. */ > + dtv[0].counter = new_gen; > +@@ -986,7 +1015,7 @@ _dl_add_to_slotinfo (struct link_map *l, bool do_add) > + the first slot. */ > + assert (idx == 0); > + > +- listp = prevp->next = (struct dtv_slotinfo_list *) > ++ listp = (struct dtv_slotinfo_list *) > + malloc (sizeof (struct dtv_slotinfo_list) > + + TLS_SLOTINFO_SURPLUS * sizeof (struct dtv_slotinfo)); > + if (listp == NULL) > +@@ -1000,6 +1029,8 @@ cannot create TLS data structures")); > + listp->next = NULL; > + memset (listp->slotinfo, '\0', > + TLS_SLOTINFO_SURPLUS * sizeof (struct dtv_slotinfo)); > ++ /* Synchronize with _dl_update_slotinfo. */ > ++ atomic_store_release (&prevp->next, listp); > + } > + > + /* Add the information into the slotinfo data structure. */ > +-- > +2.27.0 > diff --git a/meta/recipes-core/glibc/glibc/0032-elf-Use-relaxed-atomics-for-racy-accesses-BZ-19329.patch b/meta/recipes-core/glibc/glibc/0032-elf-Use-relaxed-atomics-for-racy-accesses-BZ-19329.patch > new file mode 100644 > index 0000000..eb8ef31 > --- /dev/null > +++ b/meta/recipes-core/glibc/glibc/0032-elf-Use-relaxed-atomics-for-racy-accesses-BZ-19329.patch > @@ -0,0 +1,206 @@ > +From f4f8f4d4e0f92488431b268c8cd9555730b9afe9 Mon Sep 17 00:00:00 2001 > +From: Szabolcs Nagy <szabolcs.nagy@arm.com> > +Date: Wed, 30 Dec 2020 19:19:37 +0000 > +Subject: [PATCH] elf: Use relaxed atomics for racy accesses [BZ #19329] > + > +This is a follow up patch to the fix for bug 19329. This adds relaxed > +MO atomics to accesses that were previously data races but are now > +race conditions, and where relaxed MO is sufficient. > + > +The race conditions all follow the pattern that the write is behind the > +dlopen lock, but a read can happen concurrently (e.g. during tls access) > +without holding the lock. For slotinfo entries the read value only > +matters if it reads from a synchronized write in dlopen or dlclose, > +otherwise the related dtv entry is not valid to access so it is fine > +to leave it in an inconsistent state. The same applies for > +GL(dl_tls_max_dtv_idx) and GL(dl_tls_generation), but there the > +algorithm relies on the fact that the read of the last synchronized > +write is an increasing value. > + > +Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> > +--- > + elf/dl-close.c | 20 +++++++++++++------- > + elf/dl-open.c | 5 ++++- > + elf/dl-tls.c | 31 +++++++++++++++++++++++-------- > + sysdeps/x86_64/dl-tls.c | 3 ++- > + 4 files changed, 42 insertions(+), 17 deletions(-) > +--- > +Upstream-Status: Backport [https://sourceware.org/git/?p=glibc.git;a=patch;h=f4f8f4d4e0f92488431b268c8cd9555730b9afe9] > +Comment: Hunks from elf/dl-open.c and elf/dl-tls.c are refreshed due to offset change. > +Signed-off-by: Akash Hadke <akash.hadke@kpit.com> > +Signed-off-by: Akash Hadke <hadkeakash4@gmail.com> > +--- > +diff --git a/elf/dl-close.c b/elf/dl-close.c > +index c51becd06b..3720e47dd1 100644 > +--- a/elf/dl-close.c > ++++ b/elf/dl-close.c > +@@ -79,9 +79,10 @@ remove_slotinfo (size_t idx, struct dtv_slotinfo_list *listp, size_t disp, > + { > + assert (old_map->l_tls_modid == idx); > + > +- /* Mark the entry as unused. */ > +- listp->slotinfo[idx - disp].gen = GL(dl_tls_generation) + 1; > +- listp->slotinfo[idx - disp].map = NULL; > ++ /* Mark the entry as unused. These can be read concurrently. */ > ++ atomic_store_relaxed (&listp->slotinfo[idx - disp].gen, > ++ GL(dl_tls_generation) + 1); > ++ atomic_store_relaxed (&listp->slotinfo[idx - disp].map, NULL); > + } > + > + /* If this is not the last currently used entry no need to look > +@@ -96,8 +97,8 @@ remove_slotinfo (size_t idx, struct dtv_slotinfo_list *listp, size_t disp, > + > + if (listp->slotinfo[idx - disp].map != NULL) > + { > +- /* Found a new last used index. */ > +- GL(dl_tls_max_dtv_idx) = idx; > ++ /* Found a new last used index. This can be read concurrently. */ > ++ atomic_store_relaxed (&GL(dl_tls_max_dtv_idx), idx); > + return true; > + } > + } > +@@ -571,7 +572,9 @@ _dl_close_worker (struct link_map *map, bool force) > + GL(dl_tls_dtv_slotinfo_list), 0, > + imap->l_init_called)) > + /* All dynamically loaded modules with TLS are unloaded. */ > +- GL(dl_tls_max_dtv_idx) = GL(dl_tls_static_nelem); > ++ /* Can be read concurrently. */ > ++ atomic_store_relaxed (&GL(dl_tls_max_dtv_idx), > ++ GL(dl_tls_static_nelem)); > + > + if (imap->l_tls_offset != NO_TLS_OFFSET > + && imap->l_tls_offset != FORCED_DYNAMIC_TLS_OFFSET) > +@@ -769,8 +772,11 @@ _dl_close_worker (struct link_map *map, bool force) > + /* If we removed any object which uses TLS bump the generation counter. */ > + if (any_tls) > + { > +- if (__glibc_unlikely (++GL(dl_tls_generation) == 0)) > ++ size_t newgen = GL(dl_tls_generation) + 1; > ++ if (__glibc_unlikely (newgen == 0)) > + _dl_fatal_printf ("TLS generation counter wrapped! Please report as described in "REPORT_BUGS_TO".\n"); > ++ /* Can be read concurrently. */ > ++ atomic_store_relaxed (&GL(dl_tls_generation), newgen); > + > + if (tls_free_end == GL(dl_tls_static_used)) > + GL(dl_tls_static_used) = tls_free_start; > +diff --git a/elf/dl-open.c b/elf/dl-open.c > +index 09f0df7d38..bb79ef00f1 100644 > +--- a/elf/dl-open.c > ++++ b/elf/dl-open.c > +@@ -387,9 +387,12 @@ > + } > + } > + > +- if (__builtin_expect (++GL(dl_tls_generation) == 0, 0)) > ++ size_t newgen = GL(dl_tls_generation) + 1; > ++ if (__glibc_unlikely (newgen == 0)) > + _dl_fatal_printf (N_("\ > + TLS generation counter wrapped! Please report this.")); > ++ /* Can be read concurrently. */ > ++ atomic_store_relaxed (&GL(dl_tls_generation), newgen); > + > + /* We need a second pass for static tls data, because > + _dl_update_slotinfo must not be run while calls to > +diff --git a/elf/dl-tls.c b/elf/dl-tls.c > +index 94f3cdbae0..dc69cd984e 100644 > +--- a/elf/dl-tls.c > ++++ b/elf/dl-tls.c > +@@ -96,7 +96,9 @@ > + /* No gaps, allocate a new entry. */ > + nogaps: > + > +- result = ++GL(dl_tls_max_dtv_idx); > ++ result = GL(dl_tls_max_dtv_idx) + 1; > ++ /* Can be read concurrently. */ > ++ atomic_store_relaxed (&GL(dl_tls_max_dtv_idx), result); > + } > + > + return result; > +@@ -279,10 +281,12 @@ > + dtv_t *dtv; > + size_t dtv_length; > + > ++ /* Relaxed MO, because the dtv size is later rechecked, not relied on. */ > ++ size_t max_modid = atomic_load_relaxed (&GL(dl_tls_max_dtv_idx)); > + /* We allocate a few more elements in the dtv than are needed for the > + initial set of modules. This should avoid in most cases expansions > + of the dtv. */ > +- dtv_length = GL(dl_tls_max_dtv_idx) + DTV_SURPLUS; > ++ dtv_length = max_modid + DTV_SURPLUS; > + dtv = calloc (dtv_length + 2, sizeof (dtv_t)); > + if (dtv != NULL) > + { > +@@ -687,7 +691,7 @@ > + if (modid > max_modid) > + break; > + > +- size_t gen = listp->slotinfo[cnt].gen; > ++ size_t gen = atomic_load_relaxed (&listp->slotinfo[cnt].gen); > + > + if (gen > new_gen) > + /* Not relevant. */ > +@@ -699,7 +703,8 @@ > + continue; > + > + /* If there is no map this means the entry is empty. */ > +- struct link_map *map = listp->slotinfo[cnt].map; > ++ struct link_map *map > ++ = atomic_load_relaxed (&listp->slotinfo[cnt].map); > + /* Check whether the current dtv array is large enough. */ > + if (dtv[-1].counter < modid) > + { > +@@ -843,7 +848,12 @@ > + { > + dtv_t *dtv = THREAD_DTV (); > + > +- if (__glibc_unlikely (dtv[0].counter != GL(dl_tls_generation))) > ++ /* Update is needed if dtv[0].counter < the generation of the accessed > ++ module. The global generation counter is used here as it is easier > ++ to check. Synchronization for the relaxed MO access is guaranteed > ++ by user code, see CONCURRENCY NOTES in _dl_update_slotinfo. */ > ++ size_t gen = atomic_load_relaxed (&GL(dl_tls_generation)); > ++ if (__glibc_unlikely (dtv[0].counter != gen)) > + return update_get_addr (GET_ADDR_PARAM); > + > + void *p = dtv[GET_ADDR_MODULE].pointer.val; > +@@ -866,7 +876,10 @@ > + return NULL; > + > + dtv_t *dtv = THREAD_DTV (); > +- if (__glibc_unlikely (dtv[0].counter != GL(dl_tls_generation))) > ++ /* This may be called without holding the GL(dl_load_lock). Reading > ++ arbitrary gen value is fine since this is best effort code. */ > ++ size_t gen = atomic_load_relaxed (&GL(dl_tls_generation)); > ++ if (__glibc_unlikely (dtv[0].counter != gen)) > + { > + /* This thread's DTV is not completely current, > + but it might already cover this module. */ > +@@ -961,7 +974,9 @@ > + /* Add the information into the slotinfo data structure. */ > + if (do_add) > + { > +- listp->slotinfo[idx].map = l; > +- listp->slotinfo[idx].gen = GL(dl_tls_generation) + 1; > ++ /* Can be read concurrently. See _dl_update_slotinfo. */ > ++ atomic_store_relaxed (&listp->slotinfo[idx].map, l); > ++ atomic_store_relaxed (&listp->slotinfo[idx].gen, > ++ GL(dl_tls_generation) + 1); > + } > + } > + > +diff --git a/sysdeps/x86_64/dl-tls.c b/sysdeps/x86_64/dl-tls.c > +index 6595f6615b..24ef560b71 100644 > +--- a/sysdeps/x86_64/dl-tls.c > ++++ b/sysdeps/x86_64/dl-tls.c > +@@ -40,7 +40,8 @@ __tls_get_addr_slow (GET_ADDR_ARGS) > + { > + dtv_t *dtv = THREAD_DTV (); > + > +- if (__glibc_unlikely (dtv[0].counter != GL(dl_tls_generation))) > ++ size_t gen = atomic_load_relaxed (&GL(dl_tls_generation)); > ++ if (__glibc_unlikely (dtv[0].counter != gen)) > + return update_get_addr (GET_ADDR_PARAM); > + > + return tls_get_addr_tail (GET_ADDR_PARAM, dtv, NULL); > +-- > +2.27.0 > diff --git a/meta/recipes-core/glibc/glibc/0033-elf-Add-test-case-for-BZ-19329.patch b/meta/recipes-core/glibc/glibc/0033-elf-Add-test-case-for-BZ-19329.patch > new file mode 100644 > index 0000000..f22e52e > --- /dev/null > +++ b/meta/recipes-core/glibc/glibc/0033-elf-Add-test-case-for-BZ-19329.patch > @@ -0,0 +1,144 @@ > +From 9d0e30329c23b5ad736fda3f174208c25970dbce Mon Sep 17 00:00:00 2001 > +From: Szabolcs Nagy <szabolcs.nagy@arm.com> > +Date: Tue, 13 Dec 2016 12:28:41 +0000 > +Subject: [PATCH] elf: Add test case for [BZ #19329] > + > +Test concurrent dlopen and pthread_create when the loaded modules have > +TLS. This triggers dl-tls assertion failures more reliably than the > +nptl/tst-stack4 test. > + > +The dlopened module has 100 DT_NEEDED dependencies with TLS, they were > +reused from an existing TLS test. The number of created threads during > +dlopen depends on filesystem speed and hardware, but at most 3 threads > +are alive at a time to limit resource usage. > + > +Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> > +--- > + elf/Makefile | 9 ++++-- > + elf/tst-tls21.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++ > + elf/tst-tls21mod.c | 1 + > + 3 files changed, 76 insertions(+), 2 deletions(-) > + create mode 100644 elf/tst-tls21.c > + create mode 100644 elf/tst-tls21mod.c > +--- > +Upstream-Status: Backport [https://sourceware.org/git/?p=glibc.git;a=patch;h=9d0e30329c23b5ad736fda3f174208c25970dbce] > +Comment: Hunks from elf/Makefile are refreshed as per glibc 2.31 codebase. > +Signed-off-by: Akash Hadke <akash.hadke@kpit.com> > +Signed-off-by: Akash Hadke <hadkeakash4@gmail.com> > +--- > +diff --git a/elf/Makefile b/elf/Makefile > +index d3e909637a..3241cb6046 100644 > +--- a/elf/Makefile > ++++ b/elf/Makefile > +@@ -201,7 +201,7 @@ > + tst-unwind-ctor tst-unwind-main tst-audit13 \ > + tst-sonamemove-link tst-sonamemove-dlopen tst-dlopen-tlsmodid \ > + tst-dlopen-self tst-auditmany tst-initfinilazyfail tst-dlopenfail \ > +- tst-dlopenfail-2 > ++ tst-dlopenfail-2 tst-tls21 > + # reldep9 > + tests-internal += loadtest unload unload2 circleload1 \ > + neededtest neededtest2 neededtest3 neededtest4 \ > +@@ -312,7 +312,7 @@ > + tst-auditmanymod7 tst-auditmanymod8 tst-auditmanymod9 \ > + tst-initlazyfailmod tst-finilazyfailmod \ > + tst-dlopenfailmod1 tst-dlopenfaillinkmod tst-dlopenfailmod2 \ > +- tst-dlopenfailmod3 tst-ldconfig-ld-mod > ++ tst-dlopenfailmod3 tst-ldconfig-ld-mod tst-tls21mod > + # Most modules build with _ISOMAC defined, but those filtered out > + # depend on internal headers. > + modules-names-tests = $(filter-out ifuncmod% tst-libc_dlvsym-dso tst-tlsmod%,\ > +@@ -1697,5 +1697,10 @@ > + $(objpfx)tst-dlopen-nodelete-reloc-mod16.so > + LDFLAGS-tst-dlopen-nodelete-reloc-mod17.so = -Wl,--no-as-needed > + > ++# Reuses tst-tls-many-dynamic-modules > ++$(objpfx)tst-tls21: $(libdl) $(shared-thread-library) > ++$(objpfx)tst-tls21.out: $(objpfx)tst-tls21mod.so > ++$(objpfx)tst-tls21mod.so: $(tst-tls-many-dynamic-modules:%=$(objpfx)%.so) > ++ > + $(objpfx)tst-ldconfig-ld_so_conf-update.out: $(objpfx)tst-ldconfig-ld-mod.so > + $(objpfx)tst-ldconfig-ld_so_conf-update: $(libdl) > +diff --git a/elf/tst-tls21.c b/elf/tst-tls21.c > +new file mode 100644 > +index 0000000000..560bf5813a > +--- /dev/null > ++++ b/elf/tst-tls21.c > +@@ -0,0 +1,68 @@ > ++/* Test concurrent dlopen and pthread_create: BZ 19329. > ++ Copyright (C) 2021 Free Software Foundation, Inc. > ++ This file is part of the GNU C Library. > ++ > ++ The GNU C Library is free software; you can redistribute it and/or > ++ modify it under the terms of the GNU Lesser General Public > ++ License as published by the Free Software Foundation; either > ++ version 2.1 of the License, or (at your option) any later version. > ++ > ++ The GNU C Library is distributed in the hope that it will be useful, > ++ but WITHOUT ANY WARRANTY; without even the implied warranty of > ++ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU > ++ Lesser General Public License for more details. > ++ > ++ You should have received a copy of the GNU Lesser General Public > ++ License along with the GNU C Library; if not, see > ++ <http://www.gnu.org/licenses/>. */ > ++ > ++#include <dlfcn.h> > ++#include <pthread.h> > ++#include <stdio.h> > ++#include <stdatomic.h> > ++#include <support/xdlfcn.h> > ++#include <support/xthread.h> > ++ > ++#define THREADS 10000 > ++ > ++static atomic_int done; > ++ > ++static void * > ++start (void *a) > ++{ > ++ /* Load a module with many dependencies that each have TLS. */ > ++ xdlopen ("tst-tls21mod.so", RTLD_LAZY); > ++ atomic_store_explicit (&done, 1, memory_order_release); > ++ return 0; > ++} > ++ > ++static void * > ++nop (void *a) > ++{ > ++ return 0; > ++} > ++ > ++static int > ++do_test (void) > ++{ > ++ pthread_t t1, t2; > ++ int i; > ++ > ++ /* Load a module with lots of dependencies and TLS. */ > ++ t1 = xpthread_create (0, start, 0); > ++ > ++ /* Concurrently create lots of threads until dlopen is observably done. */ > ++ for (i = 0; i < THREADS; i++) > ++ { > ++ if (atomic_load_explicit (&done, memory_order_acquire) != 0) > ++ break; > ++ t2 = xpthread_create (0, nop, 0); > ++ xpthread_join (t2); > ++ } > ++ > ++ xpthread_join (t1); > ++ printf ("threads created during dlopen: %d\n", i); > ++ return 0; > ++} > ++ > ++#include <support/test-driver.c> > +diff --git a/elf/tst-tls21mod.c b/elf/tst-tls21mod.c > +new file mode 100644 > +index 0000000000..206ece4fb3 > +--- /dev/null > ++++ b/elf/tst-tls21mod.c > +@@ -0,0 +1 @@ > ++int __thread x; > +-- > +2.27.0 > diff --git a/meta/recipes-core/glibc/glibc/0034-elf-Fix-DTV-gap-reuse-logic-BZ-27135.patch b/meta/recipes-core/glibc/glibc/0034-elf-Fix-DTV-gap-reuse-logic-BZ-27135.patch > new file mode 100644 > index 0000000..a87afe3 > --- /dev/null > +++ b/meta/recipes-core/glibc/glibc/0034-elf-Fix-DTV-gap-reuse-logic-BZ-27135.patch > @@ -0,0 +1,180 @@ > +From ba33937be210da5d07f7f01709323743f66011ce Mon Sep 17 00:00:00 2001 > +From: Adhemerval Zanella <adhemerval.zanella@linaro.org> > +Date: Fri, 25 Jun 2021 10:54:12 -0300 > +Subject: [PATCH] elf: Fix DTV gap reuse logic (BZ #27135) > + > +This is updated version of the 572bd547d57a (reverted by 40ebfd016ad2) > +that fixes the _dl_next_tls_modid issues. > + > +This issue with 572bd547d57a patch is the DTV entry will be only > +update on dl_open_worker() with the update_tls_slotinfo() call after > +all dependencies are being processed by _dl_map_object_deps(). However > +_dl_map_object_deps() itself might call _dl_next_tls_modid(), and since > +the _dl_tls_dtv_slotinfo_list::map is not yet set the entry will be > +wrongly reused. > + > +This patch fixes by renaming the _dl_next_tls_modid() function to > +_dl_assign_tls_modid() and by passing the link_map so it can set > +the slotinfo value so a subsequente _dl_next_tls_modid() call will > +see the entry as allocated. > + > +The intermediary value is cleared up on remove_slotinfo() for the case > +a library fails to load with RTLD_NOW. > + > +This patch fixes BZ #27135. > + > +Checked on x86_64-linux-gnu. > + > +Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com> > +--- > + elf/dl-close.c | 8 +- > + elf/dl-load.c | 2 +- > + elf/dl-open.c | 10 -- > + elf/dl-tls.c | 17 +-- > + elf/rtld.c | 2 +- > + sysdeps/generic/ldsodefs.h | 4 +- > + 6 files changed, 349 insertions(+), 33 deletions(-) > +--- > +Upstream-Status: Backport [https://sourceware.org/git/?p=glibc.git;a=patch;h=ba33937be210da5d07f7f01709323743f66011ce] > +Comment: Removed hunks those were related to test. Hunk from elf/rtld.c is refreshed. > +Signed-off-by: Akash Hadke <akash.hadke@kpit.com> > +Signed-off-by: Akash Hadke <hadkeakash4@gmail.com> > +--- > +diff --git a/elf/dl-close.c b/elf/dl-close.c > +index 3720e47dd1..f39001cab9 100644 > +--- a/elf/dl-close.c > ++++ b/elf/dl-close.c > +@@ -77,8 +77,6 @@ remove_slotinfo (size_t idx, struct dtv_slotinfo_list *listp, size_t disp, > + object that wasn't fully set up. */ > + if (__glibc_likely (old_map != NULL)) > + { > +- assert (old_map->l_tls_modid == idx); > +- > + /* Mark the entry as unused. These can be read concurrently. */ > + atomic_store_relaxed (&listp->slotinfo[idx - disp].gen, > + GL(dl_tls_generation) + 1); > +@@ -88,7 +86,11 @@ remove_slotinfo (size_t idx, struct dtv_slotinfo_list *listp, size_t disp, > + /* If this is not the last currently used entry no need to look > + further. */ > + if (idx != GL(dl_tls_max_dtv_idx)) > +- return true; > ++ { > ++ /* There is an unused dtv entry in the middle. */ > ++ GL(dl_tls_dtv_gaps) = true; > ++ return true; > ++ } > + } > + > + while (idx - disp > (disp == 0 ? 1 + GL(dl_tls_static_nelem) : 0)) > +diff --git a/elf/dl-load.c b/elf/dl-load.c > +index a08df001af..650e4edc35 100644 > +--- a/elf/dl-load.c > ++++ b/elf/dl-load.c > +@@ -1498,7 +1498,7 @@ cannot enable executable stack as shared object requires"); > + not set up TLS data structures, so don't use them now. */ > + || __glibc_likely (GL(dl_tls_dtv_slotinfo_list) != NULL))) > + /* Assign the next available module ID. */ > +- l->l_tls_modid = _dl_next_tls_modid (); > ++ _dl_assign_tls_modid (l); > + > + #ifdef DL_AFTER_LOAD > + DL_AFTER_LOAD (l); > +diff --git a/elf/dl-open.c b/elf/dl-open.c > +index a066f39bd0..d2240d8747 100644 > +--- a/elf/dl-open.c > ++++ b/elf/dl-open.c > +@@ -899,16 +899,6 @@ no more namespaces available for dlmopen()")); > + state if relocation failed, for example. */ > + if (args.map) > + { > +- /* Maybe some of the modules which were loaded use TLS. > +- Since it will be removed in the following _dl_close call > +- we have to mark the dtv array as having gaps to fill the > +- holes. This is a pessimistic assumption which won't hurt > +- if not true. There is no need to do this when we are > +- loading the auditing DSOs since TLS has not yet been set > +- up. */ > +- if ((mode & __RTLD_AUDIT) == 0) > +- GL(dl_tls_dtv_gaps) = true; > +- > + _dl_close_worker (args.map, true); > + > + /* All l_nodelete_pending objects should have been deleted > +diff --git a/elf/dl-tls.c b/elf/dl-tls.c > +index 2b5161d10a..423e380f7c 100644 > +--- a/elf/dl-tls.c > ++++ b/elf/dl-tls.c > +@@ -126,8 +126,8 @@ oom (void) > + } > + > + > +-size_t > +-_dl_next_tls_modid (void) > ++void > ++_dl_assign_tls_modid (struct link_map *l) > + { > + size_t result; > + > +@@ -157,7 +157,11 @@ _dl_next_tls_modid (void) > + } > + > + if (result - disp < runp->len) > +- break; > ++ { > ++ /* Mark the entry as used, so any dependency see it. */ > ++ atomic_store_relaxed (&runp->slotinfo[result - disp].map, l); > ++ break; > ++ } > + > + disp += runp->len; > + } > +@@ -184,17 +188,14 @@ _dl_next_tls_modid (void) > + atomic_store_relaxed (&GL(dl_tls_max_dtv_idx), result); > + } > + > +- return result; > ++ l->l_tls_modid = result; > + } > + > + > + size_t > + _dl_count_modids (void) > + { > +- /* It is rare that we have gaps; see elf/dl-open.c (_dl_open) where > +- we fail to load a module and unload it leaving a gap. If we don't > +- have gaps then the number of modids is the current maximum so > +- return that. */ > ++ /* The count is the max unless dlclose or failed dlopen created gaps. */ > + if (__glibc_likely (!GL(dl_tls_dtv_gaps))) > + return GL(dl_tls_max_dtv_idx); > + > +diff --git a/elf/rtld.c b/elf/rtld.c > +index e3fb2a5b2a..d733359eaf 100644 > +--- a/elf/rtld.c > ++++ b/elf/rtld.c > +@@ -1612,7 +1612,7 @@ > + /* Add the dynamic linker to the TLS list if it also uses TLS. */ > + if (GL(dl_rtld_map).l_tls_blocksize != 0) > + /* Assign a module ID. Do this before loading any audit modules. */ > +- GL(dl_rtld_map).l_tls_modid = _dl_next_tls_modid (); > ++ _dl_assign_tls_modid (&GL(dl_rtld_map)); > + > + /* If we have auditing DSOs to load, do it now. */ > + bool need_security_init = true; > +diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h > +index 176394de4d..9c15259236 100644 > +--- a/sysdeps/generic/ldsodefs.h > ++++ b/sysdeps/generic/ldsodefs.h > +@@ -1171,8 +1171,8 @@ extern ElfW(Addr) _dl_sysdep_start (void **start_argptr, > + extern void _dl_sysdep_start_cleanup (void) attribute_hidden; > + > + > +-/* Determine next available module ID. */ > +-extern size_t _dl_next_tls_modid (void) attribute_hidden; > ++/* Determine next available module ID and set the L l_tls_modid. */ > ++extern void _dl_assign_tls_modid (struct link_map *l) attribute_hidden; > + > + /* Count the modules with TLS segments. */ > + extern size_t _dl_count_modids (void) attribute_hidden; > +-- > +2.27.0 > diff --git a/meta/recipes-core/glibc/glibc/0035-x86_64-Avoid-lazy-relocation-of-tlsdesc-BZ-27137.patch b/meta/recipes-core/glibc/glibc/0035-x86_64-Avoid-lazy-relocation-of-tlsdesc-BZ-27137.patch > new file mode 100644 > index 0000000..899111b > --- /dev/null > +++ b/meta/recipes-core/glibc/glibc/0035-x86_64-Avoid-lazy-relocation-of-tlsdesc-BZ-27137.patch > @@ -0,0 +1,56 @@ > +From 8f7e09f4dbdb5c815a18b8285fbc5d5d7bc17d86 Mon Sep 17 00:00:00 2001 > +From: Szabolcs Nagy <szabolcs.nagy@arm.com> > +Date: Thu, 11 Feb 2021 11:29:23 +0000 > +Subject: [PATCH] x86_64: Avoid lazy relocation of tlsdesc [BZ #27137] > + > +Lazy tlsdesc relocation is racy because the static tls optimization and > +tlsdesc management operations are done without holding the dlopen lock. > + > +This similar to the commit b7cf203b5c17dd6d9878537d41e0c7cc3d270a67 > +for aarch64, but it fixes a different race: bug 27137. > + > +Another issue is that ld auditing ignores DT_BIND_NOW and thus tries to > +relocate tlsdesc lazily, but that does not work in a BIND_NOW module > +due to missing DT_TLSDESC_PLT. Unconditionally relocating tlsdesc at > +load time fixes this bug 27721 too. > +--- > + sysdeps/x86_64/dl-machine.h | 19 ++++++++++++++----- > + 1 file changed, 14 insertions(+), 5 deletions(-) > +--- > +Upstream-Status: Backport [https://sourceware.org/git/?p=glibc.git;a=patch;h=8f7e09f4dbdb5c815a18b8285fbc5d5d7bc17d86] > +Signed-off-by: Akash Hadke <akash.hadke@kpit.com> > +Signed-off-by: Akash Hadke <hadkeakash4@gmail.com> > +--- > +diff --git a/sysdeps/x86_64/dl-machine.h b/sysdeps/x86_64/dl-machine.h > +index 103eee6c3f..9a876a371e 100644 > +--- a/sysdeps/x86_64/dl-machine.h > ++++ b/sysdeps/x86_64/dl-machine.h > +@@ -570,12 +570,21 @@ elf_machine_lazy_rel (struct link_map *map, > + } > + else if (__glibc_likely (r_type == R_X86_64_TLSDESC)) > + { > +- struct tlsdesc volatile * __attribute__((__unused__)) td = > +- (struct tlsdesc volatile *)reloc_addr; > ++ const Elf_Symndx symndx = ELFW (R_SYM) (reloc->r_info); > ++ const ElfW (Sym) *symtab = (const void *)D_PTR (map, l_info[DT_SYMTAB]); > ++ const ElfW (Sym) *sym = &symtab[symndx]; > ++ const struct r_found_version *version = NULL; > + > +- td->arg = (void*)reloc; > +- td->entry = (void*)(D_PTR (map, l_info[ADDRIDX (DT_TLSDESC_PLT)]) > +- + map->l_addr); > ++ if (map->l_info[VERSYMIDX (DT_VERSYM)] != NULL) > ++ { > ++ const ElfW (Half) *vernum = > ++ (const void *)D_PTR (map, l_info[VERSYMIDX (DT_VERSYM)]); > ++ version = &map->l_versions[vernum[symndx] & 0x7fff]; > ++ } > ++ > ++ /* Always initialize TLS descriptors completely at load time, in > ++ case static TLS is allocated for it that requires locking. */ > ++ elf_machine_rela (map, reloc, sym, version, reloc_addr, skip_ifunc); > + } > + else if (__glibc_unlikely (r_type == R_X86_64_IRELATIVE)) > + { > +-- > +2.27.0 > diff --git a/meta/recipes-core/glibc/glibc/0036-i386-Avoid-lazy-relocation-of-tlsdesc-BZ-27137.patch b/meta/recipes-core/glibc/glibc/0036-i386-Avoid-lazy-relocation-of-tlsdesc-BZ-27137.patch > new file mode 100644 > index 0000000..ad0a114 > --- /dev/null > +++ b/meta/recipes-core/glibc/glibc/0036-i386-Avoid-lazy-relocation-of-tlsdesc-BZ-27137.patch > @@ -0,0 +1,124 @@ > +From ddcacd91cc10ff92d6201eda87047d029c14158d Mon Sep 17 00:00:00 2001 > +From: Szabolcs Nagy <szabolcs.nagy@arm.com> > +Date: Thu, 11 Feb 2021 11:40:11 +0000 > +Subject: [PATCH] i386: Avoid lazy relocation of tlsdesc [BZ #27137] > + > +Lazy tlsdesc relocation is racy because the static tls optimization and > +tlsdesc management operations are done without holding the dlopen lock. > + > +This similar to the commit b7cf203b5c17dd6d9878537d41e0c7cc3d270a67 > +for aarch64, but it fixes a different race: bug 27137. > + > +On i386 the code is a bit more complicated than on x86_64 because both > +rel and rela relocs are supported. > +--- > + sysdeps/i386/dl-machine.h | 76 ++++++++++++++++++--------------------- > + 1 file changed, 34 insertions(+), 42 deletions(-) > +--- > +Upstream-Status: Backport [https://sourceware.org/git/?p=glibc.git;a=patch;h=ddcacd91cc10ff92d6201eda87047d029c14158d] > +Signed-off-by: Akash Hadke <akash.hadke@kpit.com> > +Signed-off-by: Akash Hadke <hadkeakash4@gmail.com> > +--- > +diff --git a/sysdeps/i386/dl-machine.h b/sysdeps/i386/dl-machine.h > +index 23e9cc3bfb..590b41d8d7 100644 > +--- a/sysdeps/i386/dl-machine.h > ++++ b/sysdeps/i386/dl-machine.h > +@@ -688,50 +688,32 @@ elf_machine_lazy_rel (struct link_map *map, > + } > + else if (__glibc_likely (r_type == R_386_TLS_DESC)) > + { > +- struct tlsdesc volatile * __attribute__((__unused__)) td = > +- (struct tlsdesc volatile *)reloc_addr; > +- > +- /* Handle relocations that reference the local *ABS* in a simple > +- way, so as to preserve a potential addend. */ > +- if (ELF32_R_SYM (reloc->r_info) == 0) > +- td->entry = _dl_tlsdesc_resolve_abs_plus_addend; > +- /* Given a known-zero addend, we can store a pointer to the > +- reloc in the arg position. */ > +- else if (td->arg == 0) > +- { > +- td->arg = (void*)reloc; > +- td->entry = _dl_tlsdesc_resolve_rel; > +- } > +- else > +- { > +- /* We could handle non-*ABS* relocations with non-zero addends > +- by allocating dynamically an arg to hold a pointer to the > +- reloc, but that sounds pointless. */ > +- const Elf32_Rel *const r = reloc; > +- /* The code below was borrowed from elf_dynamic_do_rel(). */ > +- const ElfW(Sym) *const symtab = > +- (const void *) D_PTR (map, l_info[DT_SYMTAB]); > ++ const Elf32_Rel *const r = reloc; > ++ /* The code below was borrowed from elf_dynamic_do_rel(). */ > ++ const ElfW(Sym) *const symtab = > ++ (const void *) D_PTR (map, l_info[DT_SYMTAB]); > + > ++ /* Always initialize TLS descriptors completely at load time, in > ++ case static TLS is allocated for it that requires locking. */ > + # ifdef RTLD_BOOTSTRAP > +- /* The dynamic linker always uses versioning. */ > +- assert (map->l_info[VERSYMIDX (DT_VERSYM)] != NULL); > ++ /* The dynamic linker always uses versioning. */ > ++ assert (map->l_info[VERSYMIDX (DT_VERSYM)] != NULL); > + # else > +- if (map->l_info[VERSYMIDX (DT_VERSYM)]) > ++ if (map->l_info[VERSYMIDX (DT_VERSYM)]) > + # endif > +- { > +- const ElfW(Half) *const version = > +- (const void *) D_PTR (map, l_info[VERSYMIDX (DT_VERSYM)]); > +- ElfW(Half) ndx = version[ELFW(R_SYM) (r->r_info)] & 0x7fff; > +- elf_machine_rel (map, r, &symtab[ELFW(R_SYM) (r->r_info)], > +- &map->l_versions[ndx], > +- (void *) (l_addr + r->r_offset), skip_ifunc); > +- } > ++ { > ++ const ElfW(Half) *const version = > ++ (const void *) D_PTR (map, l_info[VERSYMIDX (DT_VERSYM)]); > ++ ElfW(Half) ndx = version[ELFW(R_SYM) (r->r_info)] & 0x7fff; > ++ elf_machine_rel (map, r, &symtab[ELFW(R_SYM) (r->r_info)], > ++ &map->l_versions[ndx], > ++ (void *) (l_addr + r->r_offset), skip_ifunc); > ++ } > + # ifndef RTLD_BOOTSTRAP > +- else > +- elf_machine_rel (map, r, &symtab[ELFW(R_SYM) (r->r_info)], NULL, > +- (void *) (l_addr + r->r_offset), skip_ifunc); > ++ else > ++ elf_machine_rel (map, r, &symtab[ELFW(R_SYM) (r->r_info)], NULL, > ++ (void *) (l_addr + r->r_offset), skip_ifunc); > + # endif > +- } > + } > + else if (__glibc_unlikely (r_type == R_386_IRELATIVE)) > + { > +@@ -758,11 +740,21 @@ elf_machine_lazy_rela (struct link_map *map, > + ; > + else if (__glibc_likely (r_type == R_386_TLS_DESC)) > + { > +- struct tlsdesc volatile * __attribute__((__unused__)) td = > +- (struct tlsdesc volatile *)reloc_addr; > ++ const Elf_Symndx symndx = ELFW (R_SYM) (reloc->r_info); > ++ const ElfW (Sym) *symtab = (const void *)D_PTR (map, l_info[DT_SYMTAB]); > ++ const ElfW (Sym) *sym = &symtab[symndx]; > ++ const struct r_found_version *version = NULL; > ++ > ++ if (map->l_info[VERSYMIDX (DT_VERSYM)] != NULL) > ++ { > ++ const ElfW (Half) *vernum = > ++ (const void *)D_PTR (map, l_info[VERSYMIDX (DT_VERSYM)]); > ++ version = &map->l_versions[vernum[symndx] & 0x7fff]; > ++ } > + > +- td->arg = (void*)reloc; > +- td->entry = _dl_tlsdesc_resolve_rela; > ++ /* Always initialize TLS descriptors completely at load time, in > ++ case static TLS is allocated for it that requires locking. */ > ++ elf_machine_rela (map, reloc, sym, version, reloc_addr, skip_ifunc); > + } > + else if (__glibc_unlikely (r_type == R_386_IRELATIVE)) > + { > +-- > +2.27.0 > diff --git a/meta/recipes-core/glibc/glibc/0037-Avoid-deadlock-between-pthread_create-and-ctors.patch b/meta/recipes-core/glibc/glibc/0037-Avoid-deadlock-between-pthread_create-and-ctors.patch > new file mode 100644 > index 0000000..7a10131 > --- /dev/null > +++ b/meta/recipes-core/glibc/glibc/0037-Avoid-deadlock-between-pthread_create-and-ctors.patch > @@ -0,0 +1,276 @@ > +From 83b5323261bb72313bffcf37476c1b8f0847c736 Mon Sep 17 00:00:00 2001 > +From: Szabolcs Nagy <szabolcs.nagy@arm.com> > +Date: Wed, 15 Sep 2021 15:16:19 +0100 > +Subject: [PATCH] elf: Avoid deadlock between pthread_create and ctors [BZ > + #28357] > + > +The fix for bug 19329 caused a regression such that pthread_create can > +deadlock when concurrent ctors from dlopen are waiting for it to finish. > +Use a new GL(dl_load_tls_lock) in pthread_create that is not taken > +around ctors in dlopen. > + > +The new lock is also used in __tls_get_addr instead of GL(dl_load_lock). > + > +The new lock is held in _dl_open_worker and _dl_close_worker around > +most of the logic before/after the init/fini routines. When init/fini > +routines are running then TLS is in a consistent, usable state. > +In _dl_open_worker the new lock requires catching and reraising dlopen > +failures that happen in the critical section. > + > +The new lock is reinitialized in a fork child, to keep the existing > +behaviour and it is kept recursive in case malloc interposition or TLS > +access from signal handlers can retake it. It is not obvious if this > +is necessary or helps, but avoids changing the preexisting behaviour. > + > +The new lock may be more appropriate for dl_iterate_phdr too than > +GL(dl_load_write_lock), since TLS state of an incompletely loaded > +module may be accessed. If the new lock can replace the old one, > +that can be a separate change. > + > +Fixes bug 28357. > + > +Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> > +--- > + elf/dl-close.c | 6 ++ > + elf/dl-open.c | 35 ++++++++- > + elf/dl-support.c | 7 ++ > + elf/dl-tls.c | 16 ++--- > + elf/rtld.c | 1 + > + sysdeps/nptl/fork.c | 3 + > + sysdeps/generic/ldsodefs.h | 9 ++- > + 10 files changed, 235 insertions(+), 12 deletions(-) > +--- > +Upstream-Status: Backport [https://sourceware.org/git/?p=glibc.git;a=patch;h=024a7640ab9ecea80e527f4e4d7f7a1868e952c5] > +Comment: This patch is refreshed for glibc 2.31. In upstream glibc 2.34 multiple src files are shuffled, updated this patch as per the code present in glibc 2.31. Removed test case. > +Signed-off-by: Akash Hadke <akash.hadke@kpit.com> > +Signed-off-by: Akash Hadke <hadkeakash4@gmail.com> > +--- > +diff --git a/elf/dl-close.c b/elf/dl-close.c > +index 93ff5c96e9..cfe0f1c0c9 100644 > +--- a/elf/dl-close.c > ++++ b/elf/dl-close.c > +@@ -551,6 +551,9 @@ > + size_t tls_free_end; > + tls_free_start = tls_free_end = NO_TLS_OFFSET; > + > ++ /* Protects global and module specitic TLS state. */ > ++ __rtld_lock_lock_recursive (GL(dl_load_tls_lock)); > ++ > + /* We modify the list of loaded objects. */ > + __rtld_lock_lock_recursive (GL(dl_load_write_lock)); > + > +@@ -786,6 +789,9 @@ > + GL(dl_tls_static_used) = tls_free_start; > + } > + > ++ /* TLS is cleaned up for the unloaded modules. */ > ++ __rtld_lock_unlock_recursive (GL(dl_load_tls_lock)); > ++ > + #ifdef SHARED > + /* Auditing checkpoint: we have deleted all objects. */ > + if (__glibc_unlikely (do_audit)) > +diff --git a/elf/dl-open.c b/elf/dl-open.c > +index 5295e931b0..6ea5dd2457 100644 > +--- a/elf/dl-open.c > ++++ b/elf/dl-open.c > +@@ -57,6 +57,9 @@ > + (non-negative). */ > + unsigned int original_global_scope_pending_adds; > + > ++ /* Set to true if the end of dl_open_worker_begin was reached. */ > ++ bool worker_continue; > ++ > + /* Original parameters to the program and the current environment. */ > + int argc; > + char **argv; > +@@ -473,7 +473,7 @@ > + } > + > + static void > +-dl_open_worker (void *a) > ++dl_open_worker_begin (void *a) > + { > + struct dl_open_args *args = a; > + const char *file = args->file; > +@@ -747,6 +747,36 @@ > + if (mode & RTLD_GLOBAL) > + add_to_global_resize (new); > + > ++ args->worker_continue = true; > ++} > ++ > ++static void > ++dl_open_worker (void *a) > ++{ > ++ struct dl_open_args *args = a; > ++ > ++ args->worker_continue = false; > ++ > ++ { > ++ /* Protects global and module specific TLS state. */ > ++ __rtld_lock_lock_recursive (GL(dl_load_tls_lock)); > ++ > ++ struct dl_exception ex; > ++ int err = _dl_catch_exception (&ex, dl_open_worker_begin, args); > ++ > ++ __rtld_lock_unlock_recursive (GL(dl_load_tls_lock)); > ++ > ++ if (__glibc_unlikely (ex.errstring != NULL)) > ++ /* Reraise the error. */ > ++ _dl_signal_exception (err, &ex, NULL); > ++ } > ++ > ++ if (!args->worker_continue) > ++ return; > ++ > ++ int mode = args->mode; > ++ struct link_map *new = args->map; > ++ > + /* Run the initializer functions of new objects. Temporarily > + disable the exception handler, so that lazy binding failures are > + fatal. */ > +diff --git a/elf/dl-support.c b/elf/dl-support.c > +index 02e2ed72f5..d99c1f1d62 100644 > +--- a/elf/dl-support.c > ++++ b/elf/dl-support.c > +@@ -219,6 +219,13 @@ > + list of loaded objects while an object is added to or removed from > + that list. */ > + __rtld_lock_define_initialized_recursive (, _dl_load_write_lock) > ++/* This lock protects global and module specific TLS related data. > ++ E.g. it is held in dlopen and dlclose when GL(dl_tls_generation), > ++ GL(dl_tls_max_dtv_idx) or GL(dl_tls_dtv_slotinfo_list) are > ++ accessed and when TLS related relocations are processed for a > ++ module. It was introduced to keep pthread_create accessing TLS > ++ state that is being set up. */ > ++__rtld_lock_define_initialized_recursive (, _dl_load_tls_lock) > + > + > + #ifdef HAVE_AUX_VECTOR > +diff --git a/elf/dl-tls.c b/elf/dl-tls.c > +index d554ae4497..9260d2d696 100644 > +--- a/elf/dl-tls.c > ++++ b/elf/dl-tls.c > +@@ -443,7 +443,7 @@ > + size_t maxgen = 0; > + > + /* Protects global dynamic TLS related state. */ > +- __rtld_lock_lock_recursive (GL(dl_load_lock)); > ++ __rtld_lock_lock_recursive (GL(dl_load_tls_lock)); > + > + /* Check if the current dtv is big enough. */ > + if (dtv[-1].counter < GL(dl_tls_max_dtv_idx)) > +@@ -517,7 +517,7 @@ > + listp = listp->next; > + assert (listp != NULL); > + } > +- __rtld_lock_unlock_recursive (GL(dl_load_lock)); > ++ __rtld_lock_unlock_recursive (GL(dl_load_tls_lock)); > + > + /* The DTV version is up-to-date now. */ > + dtv[0].counter = maxgen; > +@@ -656,7 +656,7 @@ > + > + Here the dtv needs to be updated to new_gen generation count. > + > +- This code may be called during TLS access when GL(dl_load_lock) > ++ This code may be called during TLS access when GL(dl_load_tls_lock) > + is not held. In that case the user code has to synchronize with > + dlopen and dlclose calls of relevant modules. A module m is > + relevant if the generation of m <= new_gen and dlclose of m is > +@@ -778,11 +778,11 @@ > + if (__glibc_unlikely (the_map->l_tls_offset > + != FORCED_DYNAMIC_TLS_OFFSET)) > + { > +- __rtld_lock_lock_recursive (GL(dl_load_lock)); > ++ __rtld_lock_lock_recursive (GL(dl_load_tls_lock)); > + if (__glibc_likely (the_map->l_tls_offset == NO_TLS_OFFSET)) > + { > + the_map->l_tls_offset = FORCED_DYNAMIC_TLS_OFFSET; > +- __rtld_lock_unlock_recursive (GL(dl_load_lock)); > ++ __rtld_lock_unlock_recursive (GL(dl_load_tls_lock)); > + } > + else if (__glibc_likely (the_map->l_tls_offset > + != FORCED_DYNAMIC_TLS_OFFSET)) > +@@ -794,7 +794,7 @@ > + #else > + # error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined" > + #endif > +- __rtld_lock_unlock_recursive (GL(dl_load_lock)); > ++ __rtld_lock_unlock_recursive (GL(dl_load_tls_lock)); > + > + dtv[GET_ADDR_MODULE].pointer.to_free = NULL; > + dtv[GET_ADDR_MODULE].pointer.val = p; > +@@ -802,7 +802,7 @@ > + return (char *) p + GET_ADDR_OFFSET; > + } > + else > +- __rtld_lock_unlock_recursive (GL(dl_load_lock)); > ++ __rtld_lock_unlock_recursive (GL(dl_load_tls_lock)); > + } > + struct dtv_pointer result = allocate_and_init (the_map); > + dtv[GET_ADDR_MODULE].pointer = result; > +@@ -873,7 +873,7 @@ > + return NULL; > + > + dtv_t *dtv = THREAD_DTV (); > +- /* This may be called without holding the GL(dl_load_lock). Reading > ++ /* This may be called without holding the GL(dl_load_tls_lock). Reading > + arbitrary gen value is fine since this is best effort code. */ > + size_t gen = atomic_load_relaxed (&GL(dl_tls_generation)); > + if (__glibc_unlikely (dtv[0].counter != gen)) > +diff --git a/elf/rtld.c b/elf/rtld.c > +index 8d2bba3d43..9642eb9c92 100644 > +--- a/elf/rtld.c > ++++ b/elf/rtld.c > +@@ -283,6 +283,7 @@ > + #ifdef _LIBC_REENTRANT > + ._dl_load_lock = _RTLD_LOCK_RECURSIVE_INITIALIZER, > + ._dl_load_write_lock = _RTLD_LOCK_RECURSIVE_INITIALIZER, > ++ ._dl_load_tls_lock = _RTLD_LOCK_RECURSIVE_INITIALIZER, > + #endif > + ._dl_nns = 1, > + ._dl_ns = > +diff --git a/sysdeps/nptl/fork.c b/sysdeps/nptl/fork.c > +index c471f7b15f..021691b9b7 100644 > +--- a/sysdeps/nptl/fork.c > ++++ b/sysdeps/nptl/fork.c > +@@ -125,6 +125,9 @@ > + /* Reset the lock the dynamic loader uses to protect its data. */ > + __rtld_lock_initialize (GL(dl_load_lock)); > + > ++ /* Reset the lock protecting dynamic TLS related data. */ > ++ __rtld_lock_initialize (GL(dl_load_tls_lock)); > ++ > + /* Run the handlers registered for the child. */ > + __run_fork_handlers (atfork_run_child, multiple_threads); > + } > +diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h > +index d49529da0d..9ec1511bb0 100644 > +--- a/sysdeps/generic/ldsodefs.h > ++++ b/sysdeps/generic/ldsodefs.h > +@@ -369,6 +369,13 @@ > + list of loaded objects while an object is added to or removed > + from that list. */ > + __rtld_lock_define_recursive (EXTERN, _dl_load_write_lock) > ++ /* This lock protects global and module specific TLS related data. > ++ E.g. it is held in dlopen and dlclose when GL(dl_tls_generation), > ++ GL(dl_tls_max_dtv_idx) or GL(dl_tls_dtv_slotinfo_list) are > ++ accessed and when TLS related relocations are processed for a > ++ module. It was introduced to keep pthread_create accessing TLS > ++ state that is being set up. */ > ++ __rtld_lock_define_recursive (EXTERN, _dl_load_tls_lock) > + > + /* Incremented whenever something may have been added to dl_loaded. */ > + EXTERN unsigned long long _dl_load_adds; > +@@ -1153,7 +1160,7 @@ > + > + /* Add module to slot information data. If DO_ADD is false, only the > + required memory is allocated. Must be called with GL > +- (dl_load_lock) acquired. If the function has already been called > ++ (dl_load_tls_lock) acquired. If the function has already been called > + for the link map L with !do_add, then this function will not raise > + an exception, otherwise it is possible that it encounters a memory > + allocation failure. */ > +-- > +2.27.0 > diff --git a/meta/recipes-core/glibc/glibc_2.31.bb b/meta/recipes-core/glibc/glibc_2.31.bb > index 3a3586f..4a545cb 100644 > --- a/meta/recipes-core/glibc/glibc_2.31.bb > +++ b/meta/recipes-core/glibc/glibc_2.31.bb > @@ -70,6 +70,14 @@ SRC_URI = "${GLIBC_GIT_URI};branch=${SRCBRANCH};name=glibc \ > file://CVE-2021-33574_1.patch \ > file://CVE-2021-33574_2.patch \ > file://CVE-2021-38604.patch \ > + file://0030-elf-Refactor_dl_update-slotinfo-to-avoid-use-after-free.patch \ > + file://0031-elf-Fix-data-races-in-pthread_create-and-TLS-access-BZ-19329.patch \ > + file://0032-elf-Use-relaxed-atomics-for-racy-accesses-BZ-19329.patch \ > + file://0033-elf-Add-test-case-for-BZ-19329.patch \ > + file://0034-elf-Fix-DTV-gap-reuse-logic-BZ-27135.patch \ > + file://0035-x86_64-Avoid-lazy-relocation-of-tlsdesc-BZ-27137.patch \ > + file://0036-i386-Avoid-lazy-relocation-of-tlsdesc-BZ-27137.patch \ > + file://0037-Avoid-deadlock-between-pthread_create-and-ctors.patch \ > " > S = "${WORKDIR}/git" > B = "${WORKDIR}/build-${TARGET_SYS}" > -- > 2.7.4 > > > -=-=-=-=-=-=-=-=-=-=-=- > Links: You receive all messages sent to this group. > View/Reply Online (#160000): https://lists.openembedded.org/g/openembedded-core/message/160000 > Mute This Topic: https://lists.openembedded.org/mt/87934753/3620601 > Group Owner: openembedded-core+owner@lists.openembedded.org > Unsubscribe: https://lists.openembedded.org/g/openembedded-core/unsub [steve@sakoman.com] > -=-=-=-=-=-=-=-=-=-=-=- >
On Fri, Dec 24, 2021 at 06:24:43AM -1000, Steve Sakoman wrote: > On Fri, Dec 24, 2021 at 12:42 AM akash hadke via > lists.openembedded.org <akash.hadke=kpit.com@lists.openembedded.org> > wrote: > > > > Inconsistency detected by ld.so: dl-tls.c: 493: _dl_allocate_tls_init: Assertion `listp->slotinfo[cnt].gen <= _rtld_local._dl_tls_generation' failed! > > caused by dlopen (in _dl_add_to_slotinfo and in dl_open_worker) doing > > listp->slotinfo[idx].gen = GL(dl_tls_generation) + 1; > > //... > > if (any_tls && __builtin_expect (++GL(dl_tls_generation) == 0, 0)) > > while pthread_create (in _dl_allocate_tls_init) concurrently doing > > assert (listp->slotinfo[cnt].gen <= GL(dl_tls_generation)); > > > > Backported below patch that can fix the following bugs with a lock > > that prevents DTV setup running concurrently with dlopen or dlclose. > > > > Bug 19329: https://sourceware.org/bugzilla/show_bug.cgi?id=19329 > > Bug 27111: https://sourceware.org/bugzilla/show_bug.cgi?id=27111 > > > > Patch: 0031-elf-Fix-data-races-in-pthread_create-and-TLS-access-BZ-19329.patch > > Link: https://sourceware.org/git/?p=glibc.git;a=patch;h=1387ad6225c2222f027790e3f460e31aa5dd2c54 > > > > It requires a supporting patch > > 0030-elf-Refactor_dl_update-slotinfo-to-avoid-use-after-free.patch > > Link: https://sourceware.org/git/?p=glibc.git;a=patch;h=c0669ae1a629e16b536bf11cdd0865e0dbcf4bee > > > > After adding the above fix there is a number of racy read accesses > > to globals that will be changed to relaxed MO atomics in follow-up > > patch given below. > > > > This fixes the regressions and avoids cluttering the main part > > of the fix. > > > > 0032-elf-Use-relaxed-atomics-for-racy-accesses-BZ-19329.patch > > Link: https://sourceware.org/git/?p=glibc.git;a=patch;h=f4f8f4d4e0f92488431b268c8cd9555730b9afe9 > > > > Backported the below patch to add the test to check the added fix. > > 0033-elf-Add-test-case-for-BZ-19329.patch > > Link: https://sourceware.org/git/?p=glibc.git;a=patch;h=9d0e30329c23b5ad736fda3f174208c25970dbce > > > > Previously modids were never resused for a > > different module, but after dlopen failure all gaps are reused > > not just the ones caused by the unfinished dlopened. > > > > The code has to handle reused modids already which seems to > > work, however the data races at thread creation and tls access > > (see bug 19329 and bug 27111) may be more severe if slots are > > reused. Fixing the races are not simpler if reuse is disallowed > > and reuse has other benefits so upstream added fix > > https://sourceware.org/git/?p=glibc.git;a=commit;h=572bd547d57a39b6cf0ea072545dc4048921f4c3 > > for the following bug. > > > > Bug 27135: https://sourceware.org/bugzilla/show_bug.cgi?id=27135 > > > > But in glibc upstream the commit 572bd547d57a was reverted as the > > issue with 572bd547d57a patch was the DTV entry only updated on > > dl_open_worker() with the update_tls_slotinfo() call after all > > dependencies are being processed by _dl_map_object_deps(). However > > _dl_map_object_deps() itself might call _dl_next_tls_modid(), > > and since the _dl_tls_dtv_slotinfo_list::map was not yet set the > > entry can be wrongly reused. > > > > So added below patch to fix Bug 27135. > > 0034-elf-Fix-DTV-gap-reuse-logic-BZ-27135.patch > > Link: https://sourceware.org/git/?p=glibc.git;a=patch;h=ba33937be210da5d07f7f01709323743f66011ce > > > > Not all TLS access related data races got fixed by adding > > 0031-elf-Fix-data-races-in-pthread_create-and-TLS-access-BZ-19329.patch, > > there are additional races at lazy tlsdesc relocations. > > Bug 27137: https://sourceware.org/bugzilla/show_bug.cgi?id=27137 > > > > Backported below patches to fix this issue. > > > > 0035-x86_64-Avoid-lazy-relocation-of-tlsdesc-BZ-27137.patch > > Link: https://sourceware.org/git/?p=glibc.git;a=patch;h=8f7e09f4dbdb5c815a18b8285fbc5d5d7bc17d86 > > > > 0036-i386-Avoid-lazy-relocation-of-tlsdesc-BZ-27137.patch > > Link: https://sourceware.org/git/?p=glibc.git;a=patch;h=ddcacd91cc10ff92d6201eda87047d029c14158d > > > > The fix 0031-elf-Fix-data-races-in-pthread_create-and-TLS-access-BZ-19329.patch > > for bug 19329 caused a regression such that pthread_create can > > deadlock when concurrent ctors from dlopen are waiting for it > > to finish. > > Bug 28357: https://sourceware.org/bugzilla/show_bug.cgi?id=28357 > > > > Backported below patch to fix this issue. > > 0037-Avoid-deadlock-between-pthread_create-and-ctors.patch > > Link: https://sourceware.org/git/?p=glibc.git;a=patch;h=024a7640ab9ecea80e527f4e4d7f7a1868e952c5 > > > > Signed-off-by: Akash Hadke <akash.hadke@kpit.com> > > Signed-off-by: Akash Hadke <hadkeakash4@gmail.com> > > This is a quite extensive change set. I'd like to get Khem's opinion > as glibc maintainer. Thoughts, Khem? If not clear, this fixes a rare crash in dlopen(). Saw this in automated testing but it is quite rare and non-trivial to hit. -Mikko
diff --git a/meta/recipes-core/glibc/glibc/0030-elf-Refactor_dl_update-slotinfo-to-avoid-use-after-free.patch b/meta/recipes-core/glibc/glibc/0030-elf-Refactor_dl_update-slotinfo-to-avoid-use-after-free.patch new file mode 100644 index 0000000..dba491f --- /dev/null +++ b/meta/recipes-core/glibc/glibc/0030-elf-Refactor_dl_update-slotinfo-to-avoid-use-after-free.patch @@ -0,0 +1,66 @@ +From c0669ae1a629e16b536bf11cdd0865e0dbcf4bee Mon Sep 17 00:00:00 2001 +From: Szabolcs Nagy <szabolcs.nagy@arm.com> +Date: Wed, 30 Dec 2020 21:52:38 +0000 +Subject: [PATCH] elf: Refactor _dl_update_slotinfo to avoid use after free + +map is not valid to access here because it can be freed by a concurrent +dlclose: during tls access (via __tls_get_addr) _dl_update_slotinfo is +called without holding dlopen locks. So don't check the modid of map. + +The map == 0 and map != 0 code paths can be shared (avoiding the dtv +resize in case of map == 0 is just an optimization: larger dtv than +necessary would be fine too). + +Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> +--- + elf/dl-tls.c | 21 +++++---------------- + 1 file changed, 5 insertions(+), 16 deletions(-) +--- +Upstream-Status: Backport [https://sourceware.org/git/?p=glibc.git;a=patch;h=c0669ae1a629e16b536bf11cdd0865e0dbcf4bee] +Signed-off-by: Akash Hadke <akash.hadke@kpit.com> +Signed-off-by: Akash Hadke <hadkeakash4@gmail.com> +--- +diff --git a/elf/dl-tls.c b/elf/dl-tls.c +index 24d00c14ef..f8b32b3ecb 100644 +--- a/elf/dl-tls.c ++++ b/elf/dl-tls.c +@@ -743,6 +743,8 @@ _dl_update_slotinfo (unsigned long int req_modid) + { + for (size_t cnt = total == 0 ? 1 : 0; cnt < listp->len; ++cnt) + { ++ size_t modid = total + cnt; ++ + size_t gen = listp->slotinfo[cnt].gen; + + if (gen > new_gen) +@@ -758,25 +760,12 @@ _dl_update_slotinfo (unsigned long int req_modid) + + /* If there is no map this means the entry is empty. */ + struct link_map *map = listp->slotinfo[cnt].map; +- if (map == NULL) +- { +- if (dtv[-1].counter >= total + cnt) +- { +- /* If this modid was used at some point the memory +- might still be allocated. */ +- free (dtv[total + cnt].pointer.to_free); +- dtv[total + cnt].pointer.val = TLS_DTV_UNALLOCATED; +- dtv[total + cnt].pointer.to_free = NULL; +- } +- +- continue; +- } +- + /* Check whether the current dtv array is large enough. */ +- size_t modid = map->l_tls_modid; +- assert (total + cnt == modid); + if (dtv[-1].counter < modid) + { ++ if (map == NULL) ++ continue; ++ + /* Resize the dtv. */ + dtv = _dl_resize_dtv (dtv); + +-- +2.27.0 diff --git a/meta/recipes-core/glibc/glibc/0031-elf-Fix-data-races-in-pthread_create-and-TLS-access-BZ-19329.patch b/meta/recipes-core/glibc/glibc/0031-elf-Fix-data-races-in-pthread_create-and-TLS-access-BZ-19329.patch new file mode 100644 index 0000000..25beee1 --- /dev/null +++ b/meta/recipes-core/glibc/glibc/0031-elf-Fix-data-races-in-pthread_create-and-TLS-access-BZ-19329.patch @@ -0,0 +1,191 @@ +From 1387ad6225c2222f027790e3f460e31aa5dd2c54 Mon Sep 17 00:00:00 2001 +From: Szabolcs Nagy <szabolcs.nagy@arm.com> +Date: Wed, 30 Dec 2020 19:19:37 +0000 +Subject: [PATCH] elf: Fix data races in pthread_create and TLS access [BZ + #19329] + +DTV setup at thread creation (_dl_allocate_tls_init) is changed +to take the dlopen lock, GL(dl_load_lock). Avoiding data races +here without locks would require design changes: the map that is +accessed for static TLS initialization here may be concurrently +freed by dlclose. That use after free may be solved by only +locking around static TLS setup or by ensuring dlclose does not +free modules with static TLS, however currently every link map +with TLS has to be accessed at least to see if it needs static +TLS. And even if that's solved, still a lot of atomics would be +needed to synchronize DTV related globals without a lock. So fix +both bug 19329 and bug 27111 with a lock that prevents DTV setup +running concurrently with dlopen or dlclose. + +_dl_update_slotinfo at TLS access still does not use any locks +so CONCURRENCY NOTES are added to explain the synchronization. +The early exit from the slotinfo walk when max_modid is reached +is not strictly necessary, but does not hurt either. + +An incorrect acquire load was removed from _dl_resize_dtv: it +did not synchronize with any release store or fence and +synchronization is now handled separately at thread creation +and TLS access time. + +There are still a number of racy read accesses to globals that +will be changed to relaxed MO atomics in a followup patch. This +should not introduce regressions compared to existing behaviour +and avoid cluttering the main part of the fix. + +Not all TLS access related data races got fixed here: there are +additional races at lazy tlsdesc relocations see bug 27137. + +Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> +--- + elf/dl-tls.c | 63 +++++++++++++++++++++++++++++++++++++++------------- + 1 file changed, 47 insertions(+), 16 deletions(-) +--- +Upstream-Status: Backport [https://sourceware.org/git/?p=glibc.git;a=patch;h=1387ad6225c2222f027790e3f460e31aa5dd2c54] +Signed-off-by: Akash Hadke <akash.hadke@kpit.com> +Signed-off-by: Akash Hadke <hadkeakash4@gmail.com> +--- +diff --git a/elf/dl-tls.c b/elf/dl-tls.c +index 6baff0c1ea..94f3cdbae0 100644 +--- a/elf/dl-tls.c ++++ b/elf/dl-tls.c +@@ -475,14 +475,11 @@ extern dtv_t _dl_static_dtv[]; + #endif + + static dtv_t * +-_dl_resize_dtv (dtv_t *dtv) ++_dl_resize_dtv (dtv_t *dtv, size_t max_modid) + { + /* Resize the dtv. */ + dtv_t *newp; +- /* Load GL(dl_tls_max_dtv_idx) atomically since it may be written to by +- other threads concurrently. */ +- size_t newsize +- = atomic_load_acquire (&GL(dl_tls_max_dtv_idx)) + DTV_SURPLUS; ++ size_t newsize = max_modid + DTV_SURPLUS; + size_t oldsize = dtv[-1].counter; + + if (dtv == GL(dl_initial_dtv)) +@@ -528,11 +525,14 @@ _dl_allocate_tls_init (void *result) + size_t total = 0; + size_t maxgen = 0; + ++ /* Protects global dynamic TLS related state. */ ++ __rtld_lock_lock_recursive (GL(dl_load_lock)); ++ + /* Check if the current dtv is big enough. */ + if (dtv[-1].counter < GL(dl_tls_max_dtv_idx)) + { + /* Resize the dtv. */ +- dtv = _dl_resize_dtv (dtv); ++ dtv = _dl_resize_dtv (dtv, GL(dl_tls_max_dtv_idx)); + + /* Install this new dtv in the thread data structures. */ + INSTALL_DTV (result, &dtv[-1]); +@@ -600,6 +600,7 @@ _dl_allocate_tls_init (void *result) + listp = listp->next; + assert (listp != NULL); + } ++ __rtld_lock_unlock_recursive (GL(dl_load_lock)); + + /* The DTV version is up-to-date now. */ + dtv[0].counter = maxgen; +@@ -734,12 +735,29 @@ _dl_update_slotinfo (unsigned long int req_modid) + + if (dtv[0].counter < listp->slotinfo[idx].gen) + { +- /* The generation counter for the slot is higher than what the +- current dtv implements. We have to update the whole dtv but +- only those entries with a generation counter <= the one for +- the entry we need. */ ++ /* CONCURRENCY NOTES: ++ ++ Here the dtv needs to be updated to new_gen generation count. ++ ++ This code may be called during TLS access when GL(dl_load_lock) ++ is not held. In that case the user code has to synchronize with ++ dlopen and dlclose calls of relevant modules. A module m is ++ relevant if the generation of m <= new_gen and dlclose of m is ++ synchronized: a memory access here happens after the dlopen and ++ before the dlclose of relevant modules. The dtv entries for ++ relevant modules need to be updated, other entries can be ++ arbitrary. ++ ++ This e.g. means that the first part of the slotinfo list can be ++ accessed race free, but the tail may be concurrently extended. ++ Similarly relevant slotinfo entries can be read race free, but ++ other entries are racy. However updating a non-relevant dtv ++ entry does not affect correctness. For a relevant module m, ++ max_modid >= modid of m. */ + size_t new_gen = listp->slotinfo[idx].gen; + size_t total = 0; ++ size_t max_modid = atomic_load_relaxed (&GL(dl_tls_max_dtv_idx)); ++ assert (max_modid >= req_modid); + + /* We have to look through the entire dtv slotinfo list. */ + listp = GL(dl_tls_dtv_slotinfo_list); +@@ -749,12 +767,14 @@ _dl_update_slotinfo (unsigned long int req_modid) + { + size_t modid = total + cnt; + ++ /* Later entries are not relevant. */ ++ if (modid > max_modid) ++ break; ++ + size_t gen = listp->slotinfo[cnt].gen; + + if (gen > new_gen) +- /* This is a slot for a generation younger than the +- one we are handling now. It might be incompletely +- set up so ignore it. */ ++ /* Not relevant. */ + continue; + + /* If the entry is older than the current dtv layout we +@@ -771,7 +791,7 @@ _dl_update_slotinfo (unsigned long int req_modid) + continue; + + /* Resize the dtv. */ +- dtv = _dl_resize_dtv (dtv); ++ dtv = _dl_resize_dtv (dtv, max_modid); + + assert (modid <= dtv[-1].counter); + +@@ -793,8 +813,17 @@ _dl_update_slotinfo (unsigned long int req_modid) + } + + total += listp->len; ++ if (total > max_modid) ++ break; ++ ++ /* Synchronize with _dl_add_to_slotinfo. Ideally this would ++ be consume MO since we only need to order the accesses to ++ the next node after the read of the address and on most ++ hardware (other than alpha) a normal load would do that ++ because of the address dependency. */ ++ listp = atomic_load_acquire (&listp->next); + } +- while ((listp = listp->next) != NULL); ++ while (listp != NULL); + + /* This will be the new maximum generation counter. */ + dtv[0].counter = new_gen; +@@ -986,7 +1015,7 @@ _dl_add_to_slotinfo (struct link_map *l, bool do_add) + the first slot. */ + assert (idx == 0); + +- listp = prevp->next = (struct dtv_slotinfo_list *) ++ listp = (struct dtv_slotinfo_list *) + malloc (sizeof (struct dtv_slotinfo_list) + + TLS_SLOTINFO_SURPLUS * sizeof (struct dtv_slotinfo)); + if (listp == NULL) +@@ -1000,6 +1029,8 @@ cannot create TLS data structures")); + listp->next = NULL; + memset (listp->slotinfo, '\0', + TLS_SLOTINFO_SURPLUS * sizeof (struct dtv_slotinfo)); ++ /* Synchronize with _dl_update_slotinfo. */ ++ atomic_store_release (&prevp->next, listp); + } + + /* Add the information into the slotinfo data structure. */ +-- +2.27.0 diff --git a/meta/recipes-core/glibc/glibc/0032-elf-Use-relaxed-atomics-for-racy-accesses-BZ-19329.patch b/meta/recipes-core/glibc/glibc/0032-elf-Use-relaxed-atomics-for-racy-accesses-BZ-19329.patch new file mode 100644 index 0000000..eb8ef31 --- /dev/null +++ b/meta/recipes-core/glibc/glibc/0032-elf-Use-relaxed-atomics-for-racy-accesses-BZ-19329.patch @@ -0,0 +1,206 @@ +From f4f8f4d4e0f92488431b268c8cd9555730b9afe9 Mon Sep 17 00:00:00 2001 +From: Szabolcs Nagy <szabolcs.nagy@arm.com> +Date: Wed, 30 Dec 2020 19:19:37 +0000 +Subject: [PATCH] elf: Use relaxed atomics for racy accesses [BZ #19329] + +This is a follow up patch to the fix for bug 19329. This adds relaxed +MO atomics to accesses that were previously data races but are now +race conditions, and where relaxed MO is sufficient. + +The race conditions all follow the pattern that the write is behind the +dlopen lock, but a read can happen concurrently (e.g. during tls access) +without holding the lock. For slotinfo entries the read value only +matters if it reads from a synchronized write in dlopen or dlclose, +otherwise the related dtv entry is not valid to access so it is fine +to leave it in an inconsistent state. The same applies for +GL(dl_tls_max_dtv_idx) and GL(dl_tls_generation), but there the +algorithm relies on the fact that the read of the last synchronized +write is an increasing value. + +Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> +--- + elf/dl-close.c | 20 +++++++++++++------- + elf/dl-open.c | 5 ++++- + elf/dl-tls.c | 31 +++++++++++++++++++++++-------- + sysdeps/x86_64/dl-tls.c | 3 ++- + 4 files changed, 42 insertions(+), 17 deletions(-) +--- +Upstream-Status: Backport [https://sourceware.org/git/?p=glibc.git;a=patch;h=f4f8f4d4e0f92488431b268c8cd9555730b9afe9] +Comment: Hunks from elf/dl-open.c and elf/dl-tls.c are refreshed due to offset change. +Signed-off-by: Akash Hadke <akash.hadke@kpit.com> +Signed-off-by: Akash Hadke <hadkeakash4@gmail.com> +--- +diff --git a/elf/dl-close.c b/elf/dl-close.c +index c51becd06b..3720e47dd1 100644 +--- a/elf/dl-close.c ++++ b/elf/dl-close.c +@@ -79,9 +79,10 @@ remove_slotinfo (size_t idx, struct dtv_slotinfo_list *listp, size_t disp, + { + assert (old_map->l_tls_modid == idx); + +- /* Mark the entry as unused. */ +- listp->slotinfo[idx - disp].gen = GL(dl_tls_generation) + 1; +- listp->slotinfo[idx - disp].map = NULL; ++ /* Mark the entry as unused. These can be read concurrently. */ ++ atomic_store_relaxed (&listp->slotinfo[idx - disp].gen, ++ GL(dl_tls_generation) + 1); ++ atomic_store_relaxed (&listp->slotinfo[idx - disp].map, NULL); + } + + /* If this is not the last currently used entry no need to look +@@ -96,8 +97,8 @@ remove_slotinfo (size_t idx, struct dtv_slotinfo_list *listp, size_t disp, + + if (listp->slotinfo[idx - disp].map != NULL) + { +- /* Found a new last used index. */ +- GL(dl_tls_max_dtv_idx) = idx; ++ /* Found a new last used index. This can be read concurrently. */ ++ atomic_store_relaxed (&GL(dl_tls_max_dtv_idx), idx); + return true; + } + } +@@ -571,7 +572,9 @@ _dl_close_worker (struct link_map *map, bool force) + GL(dl_tls_dtv_slotinfo_list), 0, + imap->l_init_called)) + /* All dynamically loaded modules with TLS are unloaded. */ +- GL(dl_tls_max_dtv_idx) = GL(dl_tls_static_nelem); ++ /* Can be read concurrently. */ ++ atomic_store_relaxed (&GL(dl_tls_max_dtv_idx), ++ GL(dl_tls_static_nelem)); + + if (imap->l_tls_offset != NO_TLS_OFFSET + && imap->l_tls_offset != FORCED_DYNAMIC_TLS_OFFSET) +@@ -769,8 +772,11 @@ _dl_close_worker (struct link_map *map, bool force) + /* If we removed any object which uses TLS bump the generation counter. */ + if (any_tls) + { +- if (__glibc_unlikely (++GL(dl_tls_generation) == 0)) ++ size_t newgen = GL(dl_tls_generation) + 1; ++ if (__glibc_unlikely (newgen == 0)) + _dl_fatal_printf ("TLS generation counter wrapped! Please report as described in "REPORT_BUGS_TO".\n"); ++ /* Can be read concurrently. */ ++ atomic_store_relaxed (&GL(dl_tls_generation), newgen); + + if (tls_free_end == GL(dl_tls_static_used)) + GL(dl_tls_static_used) = tls_free_start; +diff --git a/elf/dl-open.c b/elf/dl-open.c +index 09f0df7d38..bb79ef00f1 100644 +--- a/elf/dl-open.c ++++ b/elf/dl-open.c +@@ -387,9 +387,12 @@ + } + } + +- if (__builtin_expect (++GL(dl_tls_generation) == 0, 0)) ++ size_t newgen = GL(dl_tls_generation) + 1; ++ if (__glibc_unlikely (newgen == 0)) + _dl_fatal_printf (N_("\ + TLS generation counter wrapped! Please report this.")); ++ /* Can be read concurrently. */ ++ atomic_store_relaxed (&GL(dl_tls_generation), newgen); + + /* We need a second pass for static tls data, because + _dl_update_slotinfo must not be run while calls to +diff --git a/elf/dl-tls.c b/elf/dl-tls.c +index 94f3cdbae0..dc69cd984e 100644 +--- a/elf/dl-tls.c ++++ b/elf/dl-tls.c +@@ -96,7 +96,9 @@ + /* No gaps, allocate a new entry. */ + nogaps: + +- result = ++GL(dl_tls_max_dtv_idx); ++ result = GL(dl_tls_max_dtv_idx) + 1; ++ /* Can be read concurrently. */ ++ atomic_store_relaxed (&GL(dl_tls_max_dtv_idx), result); + } + + return result; +@@ -279,10 +281,12 @@ + dtv_t *dtv; + size_t dtv_length; + ++ /* Relaxed MO, because the dtv size is later rechecked, not relied on. */ ++ size_t max_modid = atomic_load_relaxed (&GL(dl_tls_max_dtv_idx)); + /* We allocate a few more elements in the dtv than are needed for the + initial set of modules. This should avoid in most cases expansions + of the dtv. */ +- dtv_length = GL(dl_tls_max_dtv_idx) + DTV_SURPLUS; ++ dtv_length = max_modid + DTV_SURPLUS; + dtv = calloc (dtv_length + 2, sizeof (dtv_t)); + if (dtv != NULL) + { +@@ -687,7 +691,7 @@ + if (modid > max_modid) + break; + +- size_t gen = listp->slotinfo[cnt].gen; ++ size_t gen = atomic_load_relaxed (&listp->slotinfo[cnt].gen); + + if (gen > new_gen) + /* Not relevant. */ +@@ -699,7 +703,8 @@ + continue; + + /* If there is no map this means the entry is empty. */ +- struct link_map *map = listp->slotinfo[cnt].map; ++ struct link_map *map ++ = atomic_load_relaxed (&listp->slotinfo[cnt].map); + /* Check whether the current dtv array is large enough. */ + if (dtv[-1].counter < modid) + { +@@ -843,7 +848,12 @@ + { + dtv_t *dtv = THREAD_DTV (); + +- if (__glibc_unlikely (dtv[0].counter != GL(dl_tls_generation))) ++ /* Update is needed if dtv[0].counter < the generation of the accessed ++ module. The global generation counter is used here as it is easier ++ to check. Synchronization for the relaxed MO access is guaranteed ++ by user code, see CONCURRENCY NOTES in _dl_update_slotinfo. */ ++ size_t gen = atomic_load_relaxed (&GL(dl_tls_generation)); ++ if (__glibc_unlikely (dtv[0].counter != gen)) + return update_get_addr (GET_ADDR_PARAM); + + void *p = dtv[GET_ADDR_MODULE].pointer.val; +@@ -866,7 +876,10 @@ + return NULL; + + dtv_t *dtv = THREAD_DTV (); +- if (__glibc_unlikely (dtv[0].counter != GL(dl_tls_generation))) ++ /* This may be called without holding the GL(dl_load_lock). Reading ++ arbitrary gen value is fine since this is best effort code. */ ++ size_t gen = atomic_load_relaxed (&GL(dl_tls_generation)); ++ if (__glibc_unlikely (dtv[0].counter != gen)) + { + /* This thread's DTV is not completely current, + but it might already cover this module. */ +@@ -961,7 +974,9 @@ + /* Add the information into the slotinfo data structure. */ + if (do_add) + { +- listp->slotinfo[idx].map = l; +- listp->slotinfo[idx].gen = GL(dl_tls_generation) + 1; ++ /* Can be read concurrently. See _dl_update_slotinfo. */ ++ atomic_store_relaxed (&listp->slotinfo[idx].map, l); ++ atomic_store_relaxed (&listp->slotinfo[idx].gen, ++ GL(dl_tls_generation) + 1); + } + } + +diff --git a/sysdeps/x86_64/dl-tls.c b/sysdeps/x86_64/dl-tls.c +index 6595f6615b..24ef560b71 100644 +--- a/sysdeps/x86_64/dl-tls.c ++++ b/sysdeps/x86_64/dl-tls.c +@@ -40,7 +40,8 @@ __tls_get_addr_slow (GET_ADDR_ARGS) + { + dtv_t *dtv = THREAD_DTV (); + +- if (__glibc_unlikely (dtv[0].counter != GL(dl_tls_generation))) ++ size_t gen = atomic_load_relaxed (&GL(dl_tls_generation)); ++ if (__glibc_unlikely (dtv[0].counter != gen)) + return update_get_addr (GET_ADDR_PARAM); + + return tls_get_addr_tail (GET_ADDR_PARAM, dtv, NULL); +-- +2.27.0 diff --git a/meta/recipes-core/glibc/glibc/0033-elf-Add-test-case-for-BZ-19329.patch b/meta/recipes-core/glibc/glibc/0033-elf-Add-test-case-for-BZ-19329.patch new file mode 100644 index 0000000..f22e52e --- /dev/null +++ b/meta/recipes-core/glibc/glibc/0033-elf-Add-test-case-for-BZ-19329.patch @@ -0,0 +1,144 @@ +From 9d0e30329c23b5ad736fda3f174208c25970dbce Mon Sep 17 00:00:00 2001 +From: Szabolcs Nagy <szabolcs.nagy@arm.com> +Date: Tue, 13 Dec 2016 12:28:41 +0000 +Subject: [PATCH] elf: Add test case for [BZ #19329] + +Test concurrent dlopen and pthread_create when the loaded modules have +TLS. This triggers dl-tls assertion failures more reliably than the +nptl/tst-stack4 test. + +The dlopened module has 100 DT_NEEDED dependencies with TLS, they were +reused from an existing TLS test. The number of created threads during +dlopen depends on filesystem speed and hardware, but at most 3 threads +are alive at a time to limit resource usage. + +Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> +--- + elf/Makefile | 9 ++++-- + elf/tst-tls21.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++ + elf/tst-tls21mod.c | 1 + + 3 files changed, 76 insertions(+), 2 deletions(-) + create mode 100644 elf/tst-tls21.c + create mode 100644 elf/tst-tls21mod.c +--- +Upstream-Status: Backport [https://sourceware.org/git/?p=glibc.git;a=patch;h=9d0e30329c23b5ad736fda3f174208c25970dbce] +Comment: Hunks from elf/Makefile are refreshed as per glibc 2.31 codebase. +Signed-off-by: Akash Hadke <akash.hadke@kpit.com> +Signed-off-by: Akash Hadke <hadkeakash4@gmail.com> +--- +diff --git a/elf/Makefile b/elf/Makefile +index d3e909637a..3241cb6046 100644 +--- a/elf/Makefile ++++ b/elf/Makefile +@@ -201,7 +201,7 @@ + tst-unwind-ctor tst-unwind-main tst-audit13 \ + tst-sonamemove-link tst-sonamemove-dlopen tst-dlopen-tlsmodid \ + tst-dlopen-self tst-auditmany tst-initfinilazyfail tst-dlopenfail \ +- tst-dlopenfail-2 ++ tst-dlopenfail-2 tst-tls21 + # reldep9 + tests-internal += loadtest unload unload2 circleload1 \ + neededtest neededtest2 neededtest3 neededtest4 \ +@@ -312,7 +312,7 @@ + tst-auditmanymod7 tst-auditmanymod8 tst-auditmanymod9 \ + tst-initlazyfailmod tst-finilazyfailmod \ + tst-dlopenfailmod1 tst-dlopenfaillinkmod tst-dlopenfailmod2 \ +- tst-dlopenfailmod3 tst-ldconfig-ld-mod ++ tst-dlopenfailmod3 tst-ldconfig-ld-mod tst-tls21mod + # Most modules build with _ISOMAC defined, but those filtered out + # depend on internal headers. + modules-names-tests = $(filter-out ifuncmod% tst-libc_dlvsym-dso tst-tlsmod%,\ +@@ -1697,5 +1697,10 @@ + $(objpfx)tst-dlopen-nodelete-reloc-mod16.so + LDFLAGS-tst-dlopen-nodelete-reloc-mod17.so = -Wl,--no-as-needed + ++# Reuses tst-tls-many-dynamic-modules ++$(objpfx)tst-tls21: $(libdl) $(shared-thread-library) ++$(objpfx)tst-tls21.out: $(objpfx)tst-tls21mod.so ++$(objpfx)tst-tls21mod.so: $(tst-tls-many-dynamic-modules:%=$(objpfx)%.so) ++ + $(objpfx)tst-ldconfig-ld_so_conf-update.out: $(objpfx)tst-ldconfig-ld-mod.so + $(objpfx)tst-ldconfig-ld_so_conf-update: $(libdl) +diff --git a/elf/tst-tls21.c b/elf/tst-tls21.c +new file mode 100644 +index 0000000000..560bf5813a +--- /dev/null ++++ b/elf/tst-tls21.c +@@ -0,0 +1,68 @@ ++/* Test concurrent dlopen and pthread_create: BZ 19329. ++ Copyright (C) 2021 Free Software Foundation, Inc. ++ This file is part of the GNU C Library. ++ ++ The GNU C Library is free software; you can redistribute it and/or ++ modify it under the terms of the GNU Lesser General Public ++ License as published by the Free Software Foundation; either ++ version 2.1 of the License, or (at your option) any later version. ++ ++ The GNU C Library is distributed in the hope that it will be useful, ++ but WITHOUT ANY WARRANTY; without even the implied warranty of ++ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU ++ Lesser General Public License for more details. ++ ++ You should have received a copy of the GNU Lesser General Public ++ License along with the GNU C Library; if not, see ++ <http://www.gnu.org/licenses/>. */ ++ ++#include <dlfcn.h> ++#include <pthread.h> ++#include <stdio.h> ++#include <stdatomic.h> ++#include <support/xdlfcn.h> ++#include <support/xthread.h> ++ ++#define THREADS 10000 ++ ++static atomic_int done; ++ ++static void * ++start (void *a) ++{ ++ /* Load a module with many dependencies that each have TLS. */ ++ xdlopen ("tst-tls21mod.so", RTLD_LAZY); ++ atomic_store_explicit (&done, 1, memory_order_release); ++ return 0; ++} ++ ++static void * ++nop (void *a) ++{ ++ return 0; ++} ++ ++static int ++do_test (void) ++{ ++ pthread_t t1, t2; ++ int i; ++ ++ /* Load a module with lots of dependencies and TLS. */ ++ t1 = xpthread_create (0, start, 0); ++ ++ /* Concurrently create lots of threads until dlopen is observably done. */ ++ for (i = 0; i < THREADS; i++) ++ { ++ if (atomic_load_explicit (&done, memory_order_acquire) != 0) ++ break; ++ t2 = xpthread_create (0, nop, 0); ++ xpthread_join (t2); ++ } ++ ++ xpthread_join (t1); ++ printf ("threads created during dlopen: %d\n", i); ++ return 0; ++} ++ ++#include <support/test-driver.c> +diff --git a/elf/tst-tls21mod.c b/elf/tst-tls21mod.c +new file mode 100644 +index 0000000000..206ece4fb3 +--- /dev/null ++++ b/elf/tst-tls21mod.c +@@ -0,0 +1 @@ ++int __thread x; +-- +2.27.0 diff --git a/meta/recipes-core/glibc/glibc/0034-elf-Fix-DTV-gap-reuse-logic-BZ-27135.patch b/meta/recipes-core/glibc/glibc/0034-elf-Fix-DTV-gap-reuse-logic-BZ-27135.patch new file mode 100644 index 0000000..a87afe3 --- /dev/null +++ b/meta/recipes-core/glibc/glibc/0034-elf-Fix-DTV-gap-reuse-logic-BZ-27135.patch @@ -0,0 +1,180 @@ +From ba33937be210da5d07f7f01709323743f66011ce Mon Sep 17 00:00:00 2001 +From: Adhemerval Zanella <adhemerval.zanella@linaro.org> +Date: Fri, 25 Jun 2021 10:54:12 -0300 +Subject: [PATCH] elf: Fix DTV gap reuse logic (BZ #27135) + +This is updated version of the 572bd547d57a (reverted by 40ebfd016ad2) +that fixes the _dl_next_tls_modid issues. + +This issue with 572bd547d57a patch is the DTV entry will be only +update on dl_open_worker() with the update_tls_slotinfo() call after +all dependencies are being processed by _dl_map_object_deps(). However +_dl_map_object_deps() itself might call _dl_next_tls_modid(), and since +the _dl_tls_dtv_slotinfo_list::map is not yet set the entry will be +wrongly reused. + +This patch fixes by renaming the _dl_next_tls_modid() function to +_dl_assign_tls_modid() and by passing the link_map so it can set +the slotinfo value so a subsequente _dl_next_tls_modid() call will +see the entry as allocated. + +The intermediary value is cleared up on remove_slotinfo() for the case +a library fails to load with RTLD_NOW. + +This patch fixes BZ #27135. + +Checked on x86_64-linux-gnu. + +Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com> +--- + elf/dl-close.c | 8 +- + elf/dl-load.c | 2 +- + elf/dl-open.c | 10 -- + elf/dl-tls.c | 17 +-- + elf/rtld.c | 2 +- + sysdeps/generic/ldsodefs.h | 4 +- + 6 files changed, 349 insertions(+), 33 deletions(-) +--- +Upstream-Status: Backport [https://sourceware.org/git/?p=glibc.git;a=patch;h=ba33937be210da5d07f7f01709323743f66011ce] +Comment: Removed hunks those were related to test. Hunk from elf/rtld.c is refreshed. +Signed-off-by: Akash Hadke <akash.hadke@kpit.com> +Signed-off-by: Akash Hadke <hadkeakash4@gmail.com> +--- +diff --git a/elf/dl-close.c b/elf/dl-close.c +index 3720e47dd1..f39001cab9 100644 +--- a/elf/dl-close.c ++++ b/elf/dl-close.c +@@ -77,8 +77,6 @@ remove_slotinfo (size_t idx, struct dtv_slotinfo_list *listp, size_t disp, + object that wasn't fully set up. */ + if (__glibc_likely (old_map != NULL)) + { +- assert (old_map->l_tls_modid == idx); +- + /* Mark the entry as unused. These can be read concurrently. */ + atomic_store_relaxed (&listp->slotinfo[idx - disp].gen, + GL(dl_tls_generation) + 1); +@@ -88,7 +86,11 @@ remove_slotinfo (size_t idx, struct dtv_slotinfo_list *listp, size_t disp, + /* If this is not the last currently used entry no need to look + further. */ + if (idx != GL(dl_tls_max_dtv_idx)) +- return true; ++ { ++ /* There is an unused dtv entry in the middle. */ ++ GL(dl_tls_dtv_gaps) = true; ++ return true; ++ } + } + + while (idx - disp > (disp == 0 ? 1 + GL(dl_tls_static_nelem) : 0)) +diff --git a/elf/dl-load.c b/elf/dl-load.c +index a08df001af..650e4edc35 100644 +--- a/elf/dl-load.c ++++ b/elf/dl-load.c +@@ -1498,7 +1498,7 @@ cannot enable executable stack as shared object requires"); + not set up TLS data structures, so don't use them now. */ + || __glibc_likely (GL(dl_tls_dtv_slotinfo_list) != NULL))) + /* Assign the next available module ID. */ +- l->l_tls_modid = _dl_next_tls_modid (); ++ _dl_assign_tls_modid (l); + + #ifdef DL_AFTER_LOAD + DL_AFTER_LOAD (l); +diff --git a/elf/dl-open.c b/elf/dl-open.c +index a066f39bd0..d2240d8747 100644 +--- a/elf/dl-open.c ++++ b/elf/dl-open.c +@@ -899,16 +899,6 @@ no more namespaces available for dlmopen()")); + state if relocation failed, for example. */ + if (args.map) + { +- /* Maybe some of the modules which were loaded use TLS. +- Since it will be removed in the following _dl_close call +- we have to mark the dtv array as having gaps to fill the +- holes. This is a pessimistic assumption which won't hurt +- if not true. There is no need to do this when we are +- loading the auditing DSOs since TLS has not yet been set +- up. */ +- if ((mode & __RTLD_AUDIT) == 0) +- GL(dl_tls_dtv_gaps) = true; +- + _dl_close_worker (args.map, true); + + /* All l_nodelete_pending objects should have been deleted +diff --git a/elf/dl-tls.c b/elf/dl-tls.c +index 2b5161d10a..423e380f7c 100644 +--- a/elf/dl-tls.c ++++ b/elf/dl-tls.c +@@ -126,8 +126,8 @@ oom (void) + } + + +-size_t +-_dl_next_tls_modid (void) ++void ++_dl_assign_tls_modid (struct link_map *l) + { + size_t result; + +@@ -157,7 +157,11 @@ _dl_next_tls_modid (void) + } + + if (result - disp < runp->len) +- break; ++ { ++ /* Mark the entry as used, so any dependency see it. */ ++ atomic_store_relaxed (&runp->slotinfo[result - disp].map, l); ++ break; ++ } + + disp += runp->len; + } +@@ -184,17 +188,14 @@ _dl_next_tls_modid (void) + atomic_store_relaxed (&GL(dl_tls_max_dtv_idx), result); + } + +- return result; ++ l->l_tls_modid = result; + } + + + size_t + _dl_count_modids (void) + { +- /* It is rare that we have gaps; see elf/dl-open.c (_dl_open) where +- we fail to load a module and unload it leaving a gap. If we don't +- have gaps then the number of modids is the current maximum so +- return that. */ ++ /* The count is the max unless dlclose or failed dlopen created gaps. */ + if (__glibc_likely (!GL(dl_tls_dtv_gaps))) + return GL(dl_tls_max_dtv_idx); + +diff --git a/elf/rtld.c b/elf/rtld.c +index e3fb2a5b2a..d733359eaf 100644 +--- a/elf/rtld.c ++++ b/elf/rtld.c +@@ -1612,7 +1612,7 @@ + /* Add the dynamic linker to the TLS list if it also uses TLS. */ + if (GL(dl_rtld_map).l_tls_blocksize != 0) + /* Assign a module ID. Do this before loading any audit modules. */ +- GL(dl_rtld_map).l_tls_modid = _dl_next_tls_modid (); ++ _dl_assign_tls_modid (&GL(dl_rtld_map)); + + /* If we have auditing DSOs to load, do it now. */ + bool need_security_init = true; +diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h +index 176394de4d..9c15259236 100644 +--- a/sysdeps/generic/ldsodefs.h ++++ b/sysdeps/generic/ldsodefs.h +@@ -1171,8 +1171,8 @@ extern ElfW(Addr) _dl_sysdep_start (void **start_argptr, + extern void _dl_sysdep_start_cleanup (void) attribute_hidden; + + +-/* Determine next available module ID. */ +-extern size_t _dl_next_tls_modid (void) attribute_hidden; ++/* Determine next available module ID and set the L l_tls_modid. */ ++extern void _dl_assign_tls_modid (struct link_map *l) attribute_hidden; + + /* Count the modules with TLS segments. */ + extern size_t _dl_count_modids (void) attribute_hidden; +-- +2.27.0 diff --git a/meta/recipes-core/glibc/glibc/0035-x86_64-Avoid-lazy-relocation-of-tlsdesc-BZ-27137.patch b/meta/recipes-core/glibc/glibc/0035-x86_64-Avoid-lazy-relocation-of-tlsdesc-BZ-27137.patch new file mode 100644 index 0000000..899111b --- /dev/null +++ b/meta/recipes-core/glibc/glibc/0035-x86_64-Avoid-lazy-relocation-of-tlsdesc-BZ-27137.patch @@ -0,0 +1,56 @@ +From 8f7e09f4dbdb5c815a18b8285fbc5d5d7bc17d86 Mon Sep 17 00:00:00 2001 +From: Szabolcs Nagy <szabolcs.nagy@arm.com> +Date: Thu, 11 Feb 2021 11:29:23 +0000 +Subject: [PATCH] x86_64: Avoid lazy relocation of tlsdesc [BZ #27137] + +Lazy tlsdesc relocation is racy because the static tls optimization and +tlsdesc management operations are done without holding the dlopen lock. + +This similar to the commit b7cf203b5c17dd6d9878537d41e0c7cc3d270a67 +for aarch64, but it fixes a different race: bug 27137. + +Another issue is that ld auditing ignores DT_BIND_NOW and thus tries to +relocate tlsdesc lazily, but that does not work in a BIND_NOW module +due to missing DT_TLSDESC_PLT. Unconditionally relocating tlsdesc at +load time fixes this bug 27721 too. +--- + sysdeps/x86_64/dl-machine.h | 19 ++++++++++++++----- + 1 file changed, 14 insertions(+), 5 deletions(-) +--- +Upstream-Status: Backport [https://sourceware.org/git/?p=glibc.git;a=patch;h=8f7e09f4dbdb5c815a18b8285fbc5d5d7bc17d86] +Signed-off-by: Akash Hadke <akash.hadke@kpit.com> +Signed-off-by: Akash Hadke <hadkeakash4@gmail.com> +--- +diff --git a/sysdeps/x86_64/dl-machine.h b/sysdeps/x86_64/dl-machine.h +index 103eee6c3f..9a876a371e 100644 +--- a/sysdeps/x86_64/dl-machine.h ++++ b/sysdeps/x86_64/dl-machine.h +@@ -570,12 +570,21 @@ elf_machine_lazy_rel (struct link_map *map, + } + else if (__glibc_likely (r_type == R_X86_64_TLSDESC)) + { +- struct tlsdesc volatile * __attribute__((__unused__)) td = +- (struct tlsdesc volatile *)reloc_addr; ++ const Elf_Symndx symndx = ELFW (R_SYM) (reloc->r_info); ++ const ElfW (Sym) *symtab = (const void *)D_PTR (map, l_info[DT_SYMTAB]); ++ const ElfW (Sym) *sym = &symtab[symndx]; ++ const struct r_found_version *version = NULL; + +- td->arg = (void*)reloc; +- td->entry = (void*)(D_PTR (map, l_info[ADDRIDX (DT_TLSDESC_PLT)]) +- + map->l_addr); ++ if (map->l_info[VERSYMIDX (DT_VERSYM)] != NULL) ++ { ++ const ElfW (Half) *vernum = ++ (const void *)D_PTR (map, l_info[VERSYMIDX (DT_VERSYM)]); ++ version = &map->l_versions[vernum[symndx] & 0x7fff]; ++ } ++ ++ /* Always initialize TLS descriptors completely at load time, in ++ case static TLS is allocated for it that requires locking. */ ++ elf_machine_rela (map, reloc, sym, version, reloc_addr, skip_ifunc); + } + else if (__glibc_unlikely (r_type == R_X86_64_IRELATIVE)) + { +-- +2.27.0 diff --git a/meta/recipes-core/glibc/glibc/0036-i386-Avoid-lazy-relocation-of-tlsdesc-BZ-27137.patch b/meta/recipes-core/glibc/glibc/0036-i386-Avoid-lazy-relocation-of-tlsdesc-BZ-27137.patch new file mode 100644 index 0000000..ad0a114 --- /dev/null +++ b/meta/recipes-core/glibc/glibc/0036-i386-Avoid-lazy-relocation-of-tlsdesc-BZ-27137.patch @@ -0,0 +1,124 @@ +From ddcacd91cc10ff92d6201eda87047d029c14158d Mon Sep 17 00:00:00 2001 +From: Szabolcs Nagy <szabolcs.nagy@arm.com> +Date: Thu, 11 Feb 2021 11:40:11 +0000 +Subject: [PATCH] i386: Avoid lazy relocation of tlsdesc [BZ #27137] + +Lazy tlsdesc relocation is racy because the static tls optimization and +tlsdesc management operations are done without holding the dlopen lock. + +This similar to the commit b7cf203b5c17dd6d9878537d41e0c7cc3d270a67 +for aarch64, but it fixes a different race: bug 27137. + +On i386 the code is a bit more complicated than on x86_64 because both +rel and rela relocs are supported. +--- + sysdeps/i386/dl-machine.h | 76 ++++++++++++++++++--------------------- + 1 file changed, 34 insertions(+), 42 deletions(-) +--- +Upstream-Status: Backport [https://sourceware.org/git/?p=glibc.git;a=patch;h=ddcacd91cc10ff92d6201eda87047d029c14158d] +Signed-off-by: Akash Hadke <akash.hadke@kpit.com> +Signed-off-by: Akash Hadke <hadkeakash4@gmail.com> +--- +diff --git a/sysdeps/i386/dl-machine.h b/sysdeps/i386/dl-machine.h +index 23e9cc3bfb..590b41d8d7 100644 +--- a/sysdeps/i386/dl-machine.h ++++ b/sysdeps/i386/dl-machine.h +@@ -688,50 +688,32 @@ elf_machine_lazy_rel (struct link_map *map, + } + else if (__glibc_likely (r_type == R_386_TLS_DESC)) + { +- struct tlsdesc volatile * __attribute__((__unused__)) td = +- (struct tlsdesc volatile *)reloc_addr; +- +- /* Handle relocations that reference the local *ABS* in a simple +- way, so as to preserve a potential addend. */ +- if (ELF32_R_SYM (reloc->r_info) == 0) +- td->entry = _dl_tlsdesc_resolve_abs_plus_addend; +- /* Given a known-zero addend, we can store a pointer to the +- reloc in the arg position. */ +- else if (td->arg == 0) +- { +- td->arg = (void*)reloc; +- td->entry = _dl_tlsdesc_resolve_rel; +- } +- else +- { +- /* We could handle non-*ABS* relocations with non-zero addends +- by allocating dynamically an arg to hold a pointer to the +- reloc, but that sounds pointless. */ +- const Elf32_Rel *const r = reloc; +- /* The code below was borrowed from elf_dynamic_do_rel(). */ +- const ElfW(Sym) *const symtab = +- (const void *) D_PTR (map, l_info[DT_SYMTAB]); ++ const Elf32_Rel *const r = reloc; ++ /* The code below was borrowed from elf_dynamic_do_rel(). */ ++ const ElfW(Sym) *const symtab = ++ (const void *) D_PTR (map, l_info[DT_SYMTAB]); + ++ /* Always initialize TLS descriptors completely at load time, in ++ case static TLS is allocated for it that requires locking. */ + # ifdef RTLD_BOOTSTRAP +- /* The dynamic linker always uses versioning. */ +- assert (map->l_info[VERSYMIDX (DT_VERSYM)] != NULL); ++ /* The dynamic linker always uses versioning. */ ++ assert (map->l_info[VERSYMIDX (DT_VERSYM)] != NULL); + # else +- if (map->l_info[VERSYMIDX (DT_VERSYM)]) ++ if (map->l_info[VERSYMIDX (DT_VERSYM)]) + # endif +- { +- const ElfW(Half) *const version = +- (const void *) D_PTR (map, l_info[VERSYMIDX (DT_VERSYM)]); +- ElfW(Half) ndx = version[ELFW(R_SYM) (r->r_info)] & 0x7fff; +- elf_machine_rel (map, r, &symtab[ELFW(R_SYM) (r->r_info)], +- &map->l_versions[ndx], +- (void *) (l_addr + r->r_offset), skip_ifunc); +- } ++ { ++ const ElfW(Half) *const version = ++ (const void *) D_PTR (map, l_info[VERSYMIDX (DT_VERSYM)]); ++ ElfW(Half) ndx = version[ELFW(R_SYM) (r->r_info)] & 0x7fff; ++ elf_machine_rel (map, r, &symtab[ELFW(R_SYM) (r->r_info)], ++ &map->l_versions[ndx], ++ (void *) (l_addr + r->r_offset), skip_ifunc); ++ } + # ifndef RTLD_BOOTSTRAP +- else +- elf_machine_rel (map, r, &symtab[ELFW(R_SYM) (r->r_info)], NULL, +- (void *) (l_addr + r->r_offset), skip_ifunc); ++ else ++ elf_machine_rel (map, r, &symtab[ELFW(R_SYM) (r->r_info)], NULL, ++ (void *) (l_addr + r->r_offset), skip_ifunc); + # endif +- } + } + else if (__glibc_unlikely (r_type == R_386_IRELATIVE)) + { +@@ -758,11 +740,21 @@ elf_machine_lazy_rela (struct link_map *map, + ; + else if (__glibc_likely (r_type == R_386_TLS_DESC)) + { +- struct tlsdesc volatile * __attribute__((__unused__)) td = +- (struct tlsdesc volatile *)reloc_addr; ++ const Elf_Symndx symndx = ELFW (R_SYM) (reloc->r_info); ++ const ElfW (Sym) *symtab = (const void *)D_PTR (map, l_info[DT_SYMTAB]); ++ const ElfW (Sym) *sym = &symtab[symndx]; ++ const struct r_found_version *version = NULL; ++ ++ if (map->l_info[VERSYMIDX (DT_VERSYM)] != NULL) ++ { ++ const ElfW (Half) *vernum = ++ (const void *)D_PTR (map, l_info[VERSYMIDX (DT_VERSYM)]); ++ version = &map->l_versions[vernum[symndx] & 0x7fff]; ++ } + +- td->arg = (void*)reloc; +- td->entry = _dl_tlsdesc_resolve_rela; ++ /* Always initialize TLS descriptors completely at load time, in ++ case static TLS is allocated for it that requires locking. */ ++ elf_machine_rela (map, reloc, sym, version, reloc_addr, skip_ifunc); + } + else if (__glibc_unlikely (r_type == R_386_IRELATIVE)) + { +-- +2.27.0 diff --git a/meta/recipes-core/glibc/glibc/0037-Avoid-deadlock-between-pthread_create-and-ctors.patch b/meta/recipes-core/glibc/glibc/0037-Avoid-deadlock-between-pthread_create-and-ctors.patch new file mode 100644 index 0000000..7a10131 --- /dev/null +++ b/meta/recipes-core/glibc/glibc/0037-Avoid-deadlock-between-pthread_create-and-ctors.patch @@ -0,0 +1,276 @@ +From 83b5323261bb72313bffcf37476c1b8f0847c736 Mon Sep 17 00:00:00 2001 +From: Szabolcs Nagy <szabolcs.nagy@arm.com> +Date: Wed, 15 Sep 2021 15:16:19 +0100 +Subject: [PATCH] elf: Avoid deadlock between pthread_create and ctors [BZ + #28357] + +The fix for bug 19329 caused a regression such that pthread_create can +deadlock when concurrent ctors from dlopen are waiting for it to finish. +Use a new GL(dl_load_tls_lock) in pthread_create that is not taken +around ctors in dlopen. + +The new lock is also used in __tls_get_addr instead of GL(dl_load_lock). + +The new lock is held in _dl_open_worker and _dl_close_worker around +most of the logic before/after the init/fini routines. When init/fini +routines are running then TLS is in a consistent, usable state. +In _dl_open_worker the new lock requires catching and reraising dlopen +failures that happen in the critical section. + +The new lock is reinitialized in a fork child, to keep the existing +behaviour and it is kept recursive in case malloc interposition or TLS +access from signal handlers can retake it. It is not obvious if this +is necessary or helps, but avoids changing the preexisting behaviour. + +The new lock may be more appropriate for dl_iterate_phdr too than +GL(dl_load_write_lock), since TLS state of an incompletely loaded +module may be accessed. If the new lock can replace the old one, +that can be a separate change. + +Fixes bug 28357. + +Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> +--- + elf/dl-close.c | 6 ++ + elf/dl-open.c | 35 ++++++++- + elf/dl-support.c | 7 ++ + elf/dl-tls.c | 16 ++--- + elf/rtld.c | 1 + + sysdeps/nptl/fork.c | 3 + + sysdeps/generic/ldsodefs.h | 9 ++- + 10 files changed, 235 insertions(+), 12 deletions(-) +--- +Upstream-Status: Backport [https://sourceware.org/git/?p=glibc.git;a=patch;h=024a7640ab9ecea80e527f4e4d7f7a1868e952c5] +Comment: This patch is refreshed for glibc 2.31. In upstream glibc 2.34 multiple src files are shuffled, updated this patch as per the code present in glibc 2.31. Removed test case. +Signed-off-by: Akash Hadke <akash.hadke@kpit.com> +Signed-off-by: Akash Hadke <hadkeakash4@gmail.com> +--- +diff --git a/elf/dl-close.c b/elf/dl-close.c +index 93ff5c96e9..cfe0f1c0c9 100644 +--- a/elf/dl-close.c ++++ b/elf/dl-close.c +@@ -551,6 +551,9 @@ + size_t tls_free_end; + tls_free_start = tls_free_end = NO_TLS_OFFSET; + ++ /* Protects global and module specitic TLS state. */ ++ __rtld_lock_lock_recursive (GL(dl_load_tls_lock)); ++ + /* We modify the list of loaded objects. */ + __rtld_lock_lock_recursive (GL(dl_load_write_lock)); + +@@ -786,6 +789,9 @@ + GL(dl_tls_static_used) = tls_free_start; + } + ++ /* TLS is cleaned up for the unloaded modules. */ ++ __rtld_lock_unlock_recursive (GL(dl_load_tls_lock)); ++ + #ifdef SHARED + /* Auditing checkpoint: we have deleted all objects. */ + if (__glibc_unlikely (do_audit)) +diff --git a/elf/dl-open.c b/elf/dl-open.c +index 5295e931b0..6ea5dd2457 100644 +--- a/elf/dl-open.c ++++ b/elf/dl-open.c +@@ -57,6 +57,9 @@ + (non-negative). */ + unsigned int original_global_scope_pending_adds; + ++ /* Set to true if the end of dl_open_worker_begin was reached. */ ++ bool worker_continue; ++ + /* Original parameters to the program and the current environment. */ + int argc; + char **argv; +@@ -473,7 +473,7 @@ + } + + static void +-dl_open_worker (void *a) ++dl_open_worker_begin (void *a) + { + struct dl_open_args *args = a; + const char *file = args->file; +@@ -747,6 +747,36 @@ + if (mode & RTLD_GLOBAL) + add_to_global_resize (new); + ++ args->worker_continue = true; ++} ++ ++static void ++dl_open_worker (void *a) ++{ ++ struct dl_open_args *args = a; ++ ++ args->worker_continue = false; ++ ++ { ++ /* Protects global and module specific TLS state. */ ++ __rtld_lock_lock_recursive (GL(dl_load_tls_lock)); ++ ++ struct dl_exception ex; ++ int err = _dl_catch_exception (&ex, dl_open_worker_begin, args); ++ ++ __rtld_lock_unlock_recursive (GL(dl_load_tls_lock)); ++ ++ if (__glibc_unlikely (ex.errstring != NULL)) ++ /* Reraise the error. */ ++ _dl_signal_exception (err, &ex, NULL); ++ } ++ ++ if (!args->worker_continue) ++ return; ++ ++ int mode = args->mode; ++ struct link_map *new = args->map; ++ + /* Run the initializer functions of new objects. Temporarily + disable the exception handler, so that lazy binding failures are + fatal. */ +diff --git a/elf/dl-support.c b/elf/dl-support.c +index 02e2ed72f5..d99c1f1d62 100644 +--- a/elf/dl-support.c ++++ b/elf/dl-support.c +@@ -219,6 +219,13 @@ + list of loaded objects while an object is added to or removed from + that list. */ + __rtld_lock_define_initialized_recursive (, _dl_load_write_lock) ++/* This lock protects global and module specific TLS related data. ++ E.g. it is held in dlopen and dlclose when GL(dl_tls_generation), ++ GL(dl_tls_max_dtv_idx) or GL(dl_tls_dtv_slotinfo_list) are ++ accessed and when TLS related relocations are processed for a ++ module. It was introduced to keep pthread_create accessing TLS ++ state that is being set up. */ ++__rtld_lock_define_initialized_recursive (, _dl_load_tls_lock) + + + #ifdef HAVE_AUX_VECTOR +diff --git a/elf/dl-tls.c b/elf/dl-tls.c +index d554ae4497..9260d2d696 100644 +--- a/elf/dl-tls.c ++++ b/elf/dl-tls.c +@@ -443,7 +443,7 @@ + size_t maxgen = 0; + + /* Protects global dynamic TLS related state. */ +- __rtld_lock_lock_recursive (GL(dl_load_lock)); ++ __rtld_lock_lock_recursive (GL(dl_load_tls_lock)); + + /* Check if the current dtv is big enough. */ + if (dtv[-1].counter < GL(dl_tls_max_dtv_idx)) +@@ -517,7 +517,7 @@ + listp = listp->next; + assert (listp != NULL); + } +- __rtld_lock_unlock_recursive (GL(dl_load_lock)); ++ __rtld_lock_unlock_recursive (GL(dl_load_tls_lock)); + + /* The DTV version is up-to-date now. */ + dtv[0].counter = maxgen; +@@ -656,7 +656,7 @@ + + Here the dtv needs to be updated to new_gen generation count. + +- This code may be called during TLS access when GL(dl_load_lock) ++ This code may be called during TLS access when GL(dl_load_tls_lock) + is not held. In that case the user code has to synchronize with + dlopen and dlclose calls of relevant modules. A module m is + relevant if the generation of m <= new_gen and dlclose of m is +@@ -778,11 +778,11 @@ + if (__glibc_unlikely (the_map->l_tls_offset + != FORCED_DYNAMIC_TLS_OFFSET)) + { +- __rtld_lock_lock_recursive (GL(dl_load_lock)); ++ __rtld_lock_lock_recursive (GL(dl_load_tls_lock)); + if (__glibc_likely (the_map->l_tls_offset == NO_TLS_OFFSET)) + { + the_map->l_tls_offset = FORCED_DYNAMIC_TLS_OFFSET; +- __rtld_lock_unlock_recursive (GL(dl_load_lock)); ++ __rtld_lock_unlock_recursive (GL(dl_load_tls_lock)); + } + else if (__glibc_likely (the_map->l_tls_offset + != FORCED_DYNAMIC_TLS_OFFSET)) +@@ -794,7 +794,7 @@ + #else + # error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined" + #endif +- __rtld_lock_unlock_recursive (GL(dl_load_lock)); ++ __rtld_lock_unlock_recursive (GL(dl_load_tls_lock)); + + dtv[GET_ADDR_MODULE].pointer.to_free = NULL; + dtv[GET_ADDR_MODULE].pointer.val = p; +@@ -802,7 +802,7 @@ + return (char *) p + GET_ADDR_OFFSET; + } + else +- __rtld_lock_unlock_recursive (GL(dl_load_lock)); ++ __rtld_lock_unlock_recursive (GL(dl_load_tls_lock)); + } + struct dtv_pointer result = allocate_and_init (the_map); + dtv[GET_ADDR_MODULE].pointer = result; +@@ -873,7 +873,7 @@ + return NULL; + + dtv_t *dtv = THREAD_DTV (); +- /* This may be called without holding the GL(dl_load_lock). Reading ++ /* This may be called without holding the GL(dl_load_tls_lock). Reading + arbitrary gen value is fine since this is best effort code. */ + size_t gen = atomic_load_relaxed (&GL(dl_tls_generation)); + if (__glibc_unlikely (dtv[0].counter != gen)) +diff --git a/elf/rtld.c b/elf/rtld.c +index 8d2bba3d43..9642eb9c92 100644 +--- a/elf/rtld.c ++++ b/elf/rtld.c +@@ -283,6 +283,7 @@ + #ifdef _LIBC_REENTRANT + ._dl_load_lock = _RTLD_LOCK_RECURSIVE_INITIALIZER, + ._dl_load_write_lock = _RTLD_LOCK_RECURSIVE_INITIALIZER, ++ ._dl_load_tls_lock = _RTLD_LOCK_RECURSIVE_INITIALIZER, + #endif + ._dl_nns = 1, + ._dl_ns = +diff --git a/sysdeps/nptl/fork.c b/sysdeps/nptl/fork.c +index c471f7b15f..021691b9b7 100644 +--- a/sysdeps/nptl/fork.c ++++ b/sysdeps/nptl/fork.c +@@ -125,6 +125,9 @@ + /* Reset the lock the dynamic loader uses to protect its data. */ + __rtld_lock_initialize (GL(dl_load_lock)); + ++ /* Reset the lock protecting dynamic TLS related data. */ ++ __rtld_lock_initialize (GL(dl_load_tls_lock)); ++ + /* Run the handlers registered for the child. */ + __run_fork_handlers (atfork_run_child, multiple_threads); + } +diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h +index d49529da0d..9ec1511bb0 100644 +--- a/sysdeps/generic/ldsodefs.h ++++ b/sysdeps/generic/ldsodefs.h +@@ -369,6 +369,13 @@ + list of loaded objects while an object is added to or removed + from that list. */ + __rtld_lock_define_recursive (EXTERN, _dl_load_write_lock) ++ /* This lock protects global and module specific TLS related data. ++ E.g. it is held in dlopen and dlclose when GL(dl_tls_generation), ++ GL(dl_tls_max_dtv_idx) or GL(dl_tls_dtv_slotinfo_list) are ++ accessed and when TLS related relocations are processed for a ++ module. It was introduced to keep pthread_create accessing TLS ++ state that is being set up. */ ++ __rtld_lock_define_recursive (EXTERN, _dl_load_tls_lock) + + /* Incremented whenever something may have been added to dl_loaded. */ + EXTERN unsigned long long _dl_load_adds; +@@ -1153,7 +1160,7 @@ + + /* Add module to slot information data. If DO_ADD is false, only the + required memory is allocated. Must be called with GL +- (dl_load_lock) acquired. If the function has already been called ++ (dl_load_tls_lock) acquired. If the function has already been called + for the link map L with !do_add, then this function will not raise + an exception, otherwise it is possible that it encounters a memory + allocation failure. */ +-- +2.27.0 diff --git a/meta/recipes-core/glibc/glibc_2.31.bb b/meta/recipes-core/glibc/glibc_2.31.bb index 3a3586f..4a545cb 100644 --- a/meta/recipes-core/glibc/glibc_2.31.bb +++ b/meta/recipes-core/glibc/glibc_2.31.bb @@ -70,6 +70,14 @@ SRC_URI = "${GLIBC_GIT_URI};branch=${SRCBRANCH};name=glibc \ file://CVE-2021-33574_1.patch \ file://CVE-2021-33574_2.patch \ file://CVE-2021-38604.patch \ + file://0030-elf-Refactor_dl_update-slotinfo-to-avoid-use-after-free.patch \ + file://0031-elf-Fix-data-races-in-pthread_create-and-TLS-access-BZ-19329.patch \ + file://0032-elf-Use-relaxed-atomics-for-racy-accesses-BZ-19329.patch \ + file://0033-elf-Add-test-case-for-BZ-19329.patch \ + file://0034-elf-Fix-DTV-gap-reuse-logic-BZ-27135.patch \ + file://0035-x86_64-Avoid-lazy-relocation-of-tlsdesc-BZ-27137.patch \ + file://0036-i386-Avoid-lazy-relocation-of-tlsdesc-BZ-27137.patch \ + file://0037-Avoid-deadlock-between-pthread_create-and-ctors.patch \ " S = "${WORKDIR}/git" B = "${WORKDIR}/build-${TARGET_SYS}"