+++ This bug was initially created as a clone of Bug #1672771 +++ There are 10 missing compiler barriers in pthread_mutex_trylock.c, which can under certain circumstances, allow an optimizing compiler to reorder stores such that the kernel can observe an inconsistent state in the robust list. Stefan Liebler's (IBM) patch: https://www.sourceware.org/ml/libc-alpha/2019-02/msg00129.html My review: https://www.sourceware.org/ml/libc-alpha/2019-02/msg00133.html We should backport this to rhel-7.7, since in rhel-7.6 we did a lot of work to fix other robust mutex issues for the Samba team.
commit 823624bdc47f1f80109c9c52dee7939b9386d708 Author: Stefan Liebler <stli.com> Date: Thu Feb 7 15:18:36 2019 +0100 Add compiler barriers around modifications of the robust mutex list for pthread_mutex_trylock. [BZ #24180]
Verified with objdump based on https://bugzilla.redhat.com/show_bug.cgi?id=1672771#c7 comment, also sanity check that patch was applied.
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHSA-2019:3513