https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97868
Bug ID: 97868 Summary: warn about using fences with TSAN Product: gcc Version: 10.2.0 Status: UNCONFIRMED Keywords: diagnostic Severity: normal Priority: P3 Component: sanitizer Assignee: unassigned at gcc dot gnu.org Reporter: glisse at gcc dot gnu.org CC: dodji at gcc dot gnu.org, dvyukov at gcc dot gnu.org, jakub at gcc dot gnu.org, kcc at gcc dot gnu.org, marxin at gcc dot gnu.org Target Milestone: --- The thread sanitizer (-fsanitize=thread) does not handle C++ atomic_thread_fence. This is barely acknowledged in the documentation, but causes a number of users to waste a lot of time trying to understand how the reported race could occur. Ideally, it would be supported, but that seems hard. What does seem doable is adding a warning for programs using fences with tsan. I don't really care if it is a compile-time warning, or a runtime warning, and in the second case whether it appears as soon as a fence is executed or only as a note after reported races, as long as I get a hint about it.