On Friday 12 May 2023 at 11:32:56 +0100, Jonathan Wakely wrote: > On Fri, 12 May 2023 at 11:30, Mike Crowe <m...@mcrowe.com> wrote: > > On Thursday 11 May 2023 at 21:52:22 +0100, Jonathan Wakely wrote: > > > On Thu, 11 May 2023 at 13:42, Jonathan Wakely <jwak...@redhat.com> > > wrote: > > > > On Thu, 11 May 2023 at 13:19, Mike Crowe <m...@mcrowe.com> wrote: > > > >> However, ... > > > >> > > > >> > > diff --git a/libstdc++-v3/acinclude.m4 b/libstdc++-v3/acinclude.m4 > > > >> > > index 89e7f5f5f45..e2700b05ec3 100644 > > > >> > > --- a/libstdc++-v3/acinclude.m4 > > > >> > > +++ b/libstdc++-v3/acinclude.m4 > > > >> > > @@ -4284,7 +4284,7 @@ > > > >> AC_DEFUN([GLIBCXX_CHECK_PTHREAD_COND_CLOCKWAIT], [ > > > >> > > [glibcxx_cv_PTHREAD_COND_CLOCKWAIT=no]) > > > >> > > ]) > > > >> > > if test $glibcxx_cv_PTHREAD_COND_CLOCKWAIT = yes; then > > > >> > > - AC_DEFINE(_GLIBCXX_USE_PTHREAD_COND_CLOCKWAIT, 1, [Define if > > > >> > > pthread_cond_clockwait is available in <pthread.h>.]) > > > >> > > + AC_DEFINE(_GLIBCXX_USE_PTHREAD_COND_CLOCKWAIT, > > > >> (_GLIBCXX_TSAN==0), > > > >> > > [Define if pthread_cond_clockwait is available in <pthread.h>.]) > > > >> > > fi > > > >> > > > >> TSan does appear to have an interceptor for pthread_cond_clockwait, > > even > > > >> if > > > >> it lacks the others. Does this mean that this part is unnecessary? > > > >> > > > > > > > > Ah good point, thanks. I grepped for clocklock but not clockwait. > > > > > > > > > > In fact it seems like we don't need to change > > > _GLIBCXX_USE_PTHREAD_RWLOCK_CLOCKLOCK either, because I don't get any > > tsan > > > warnings for that. It doesn't have interceptors for > > > pthread_rwlock_{rd,wr}lock, but it doesn't complain anyway (maybe it's > > > simply not instrumenting the rwlock functions at all?!) > > > > It looks like TSan does have interceptors for pthread_rwlock_timedrdlock > > etc. I can't explain why this doesn't cause problems when libstdc++ uses > > pthread_rwlock_clockrdlock etc. > > > > I think glibc has renamed the rwlock functions, and so the interceptors no > longer work. > > # ifdef __USE_XOPEN2K > /* Try to acquire read lock for RWLOCK or return after specfied time. */ > # ifndef __USE_TIME_BITS64 > extern int pthread_rwlock_timedrdlock (pthread_rwlock_t *__restrict > __rwlock, > const struct timespec *__restrict > __abstime) __THROWNL __nonnull ((1, 2)); > # else > # ifdef __REDIRECT_NTHNL > extern int __REDIRECT_NTHNL (pthread_rwlock_timedrdlock, > (pthread_rwlock_t *__restrict __rwlock, > const struct timespec *__restrict __abstime), > __pthread_rwlock_timedrdlock64) > __nonnull ((1, 2)); > # else > # define pthread_rwlock_timedrdlock __pthread_rwlock_timedrdlock64 > # endif > # endif > # endif > > If glibc is really providing a function called > __pthread_rwlock_timedrdlock64 then will tsan be able to intercept that?
I'm by no means an expert, but I would guess not. I suspect that the renaming was introduced as part of the Y2038 fixes and TSan hasn't caught up with them either. Mike.