diff options
| author | David Lamparter <equinox@opensourcerouting.org> | 2024-06-20 11:13:20 +0200 |
|---|---|---|
| committer | David Lamparter <equinox@opensourcerouting.org> | 2024-06-20 11:16:10 +0200 |
| commit | b9541fe77fcb706c3f265d704e15f810b0a98c14 (patch) | |
| tree | 086473bb6ee4a84b56eabd934f62eea4e3b6db11 /lib/seqlock.c | |
| parent | 4836ac071409bfff65f833ce82bd5f0338d0a8ae (diff) | |
lib: use seqlock slow path with TSAN
TSAN doesn't understand the OS specific "fast" seqlock code. Use the
pthread mutex/condvar based path when TSAN is enabled.
Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
Diffstat (limited to 'lib/seqlock.c')
| -rw-r--r-- | lib/seqlock.c | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/lib/seqlock.c b/lib/seqlock.c index 62ce316920..e74e6718bf 100644 --- a/lib/seqlock.c +++ b/lib/seqlock.c @@ -26,6 +26,39 @@ * OS specific synchronization wrappers * ****************************************/ +#ifndef __has_feature /* not available on old GCC */ +#define __has_feature(x) 0 +#endif + +#if (defined(__SANITIZE_THREAD__) || __has_feature(thread_sanitizer)) +/* TSAN really does not understand what is going on with the low-level + * futex/umtx calls. This leads to a whole bunch of warnings, a lot of which + * also have _extremely_ misleading text - since TSAN does not understand that + * there is in fact a synchronization primitive involved, it can end up pulling + * in completely unrelated things. + * + * What does work is the "unsupported platform" seqlock implementation based + * on a pthread mutex + condvar, since TSAN of course suppports these. + * + * It may be possible to also fix this with TSAN annotations (__tsan_acquire + * and __tsan_release), but using those (correctly) is not easy either, and + * for now just get things rolling. + */ + +#ifdef HAVE_SYNC_LINUX_FUTEX +#undef HAVE_SYNC_LINUX_FUTEX +#endif + +#ifdef HAVE_SYNC_OPENBSD_FUTEX +#undef HAVE_SYNC_OPENBSD_FUTEX +#endif + +#ifdef HAVE_SYNC_UMTX_OP +#undef HAVE_SYNC_UMTX_OP +#endif + +#endif /* TSAN */ + /* * Linux: sys_futex() */ |