https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99572
Jonathan Wakely <redi at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution|--- |DUPLICATE
Target Milestone|15.0 |11.2
--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
This was fixed by r12-1732-ge02840c1a92abe for Bug 100806
I think the fix is correct and the FIXME in the code should be removed. It's
necessary to wake all waiters, because otherwise we can have the following
sequence:
Thread A Thread B Thread C
acquire() acquire()
release(1):
increment counter to 1
wake one thread-----\
\
\
release(1) \
increment counter to 2 \
\
\-----> decrement counter to 1
Here it should be possible for C to wake up and acquire the semaphore, but
because we only woke one thread it remains blocked. If we wake all threads then
B and C can both wake up and acquire the semaphore.
*** This bug has been marked as a duplicate of bug 100806 ***
