(In reply to [email protected] from comment #31) > The master branch has been updated by Szabolcs Nagy <[email protected]>: > > https://sourceware.org/git/gitweb.cgi?p=glibc.git; > h=1387ad6225c2222f027790e3f460e31aa5dd2c54 > > commit 1387ad6225c2222f027790e3f460e31aa5dd2c54 > Author: Szabolcs Nagy <[email protected]> > Date: Wed Dec 30 19:19:37 2020 +0000 > > 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 <[email protected]>
Hi! I think this commit may cause an ABBA deadlock problem which i mentioned in https://sourceware.org/bugzilla/show_bug.cgi?id=28331. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1863162 Title: Inconsistency detected by ld.so: dl-tls.c: 493: _dl_allocate_tls_init: Assertion `listp->slotinfo[cnt].gen <= GL(dl_tls_generation)' failed! To manage notifications about this bug go to: https://bugs.launchpad.net/glibc/+bug/1863162/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
