STINNER Victor <victor.stin...@haypocalc.com> added the comment:
> “If a signal is delivered to a thread waiting for a condition variable,
> upon return from the signal handler the thread resumes waiting for the
> condition
> variable as if it was not interrupted, or it shall return zero due to spurious
> wakeup.”
Confirmed on Linux (kernel 2.6.37, eglibc 2.11.2) using strace:
--------
10:42:59.942455 futex(0x173fabc,
FUTEX_WAIT_BITSET_PRIVATE|FUTEX_CLOCK_REALTIME, 1, {1303202584, 942432000},
ffffffff) = ? ERESTART_RESTARTBLOCK (To be restarted)
10:43:00.941777 --- SIGALRM (Alarm clock) @ 0 (0) ---
10:43:00.941848 rt_sigreturn(0x1462eac) = -1 EINTR (Interrupted system call)
10:43:00.941926 futex(0x173fabc,
FUTEX_WAIT_BITSET_PRIVATE|FUTEX_CLOCK_REALTIME, 1, {1303202584, 942432000},
ffffffff) = -1 ETIMEDOUT (Connection timed out)
10:43:04.942650 futex(0x173fae8, FUTEX_WAKE_PRIVATE, 1) = 0
--------
pthread_cond_timedwait() is interrupted: the system call returns
ERESTART_RESTARTBLOCK (To be restarted), and then the system call is restarted.
I think that we should just skip the test if Python uses pthread without
semaphore and pthread_cond_timedwait() restarts if it is interrupted by a
signal. Attached C program checks if pthread_cond_timedwait() does restart or
not. On Linux, it should be compiled using:
gcc -pthread -lrt pthread_cond_timedwait_signal.c -o
pthread_cond_timedwait_signal
I don't know how to integrate pthread_cond_timedwait_signal.c into
configure.in. I don't know if any OS does NOT restart pthread_cond_timedwait()
after an interruption, so it's maybe simpler to always skip
test_lock_acquire_interruption() and test_rlock_acquire_interruption() of
test_threadsignals if Python uses pthread without semaphore.
----------
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<http://bugs.python.org/issue11223>
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