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Revision 79761c66

ID79761c6681f0d1cc1c027116fcb4382d41ed3ece

Added by Izumi Tsutsui over 10 years ago

semaphore: fix a hangup problem under load on NetBSD hosts.

Fix following bugs in "fallback implementation of counting semaphores
with mutex+condvar" added in c166cb72f1676855816340666c3b618beef4b976:
- waiting threads are not restarted properly if more than one threads
are waiting unblock signals in qemu_sem_timedwait()
- possible missing pthread_cond_signal(3) calls when waiting threads
are returned by ETIMEDOUT
- fix an uninitialized variable
The problem is analyzed by and fix is provided by Noriyuki Soda.

Also put additional cleanup suggested by Laszlo Ersek:
- make QemuSemaphore.count unsigned (it won't be negative)
- check a return value of in pthread_cond_wait() in qemu_sem_wait()

Signed-off-by: Izumi Tsutsui <>
Reviewed-by: Laszlo Ersek <>
Message-id:
Signed-off-by: Anthony Liguori <>

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