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6 commits

Author SHA1 Message Date
Tom Cherry
ac49cedc7e Always use CLOCK_MONOTONIC for pthreads and semaphores
pthread's and semaphore's default behavior is to use CLOCK_REALTIME,
however this behavior is essentially never intended, as that clock is
prone to change discontinuously.

What users really intend is to use CLOCK_MONOTONIC, however only
pthread_cond_timedwait() provides this as an option and even there, a
large amount of existing code does not opt into CLOCK_MONOTONIC.

We have seen numerous bugs directly attributable to this difference.
Therefore, we provide this general workaround to always use
CLOCK_MONOTONIC for waiting, regardless of what the input timespec
is.

Specifically this impacts the below APIs:
pthread_mutex_timedlock()
pthread_cond_timedwait()
pthread_rwlock_timedrdlock()
pthread_rwlock_timedwrlock()
sem_timedwait()

Test: boot bullhead, boot sailfish
Test: bionic pthread/semaphore unit tests
Test: check that pthread_cond_timedwait() timeouts are uneffected by
      CLOCK_REALTIME time changes

Bug: 64694413
Bug: 64623895
Bug: 35756266
Bug: 35678943
Change-Id: Ibba98f5d88be1c306d14e9b9366302ecbef6d534
2017-08-18 09:11:05 -07:00
Elliott Hughes
5db4b6e5de Make it harder to use a broken legacy function by accident.
This function only exists for backwards compatibility, so leave it as it was.

Bug: http://b/26944282
Change-Id: I31973d1402660933103ee2d815649ab9569e4dfc
2016-04-04 16:15:37 -07:00
Elliott Hughes
dd586f2ebd sem_timedwait with a null timeout doesn't mean "forever".
It actually means "crash immediately". Well, it's an error. And callers are
much more likely to realize their mistake if we crash immediately rather
than return EINVAL. Historically, glibc has crashed and bionic -- before
the recent changes -- returned EINVAL, so this is a behavior change.

Change-Id: I0c2373a6703b20b8a97aacc1e66368a5885e8c51
2015-12-16 15:15:58 -08:00
Yabin Cui
c9a659c57b Use FUTEX_WAIT_BITSET to avoid converting timeouts.
Add unittests for pthread APIs with timeout parameter.

Bug: 17569991

Change-Id: I6b3b9b2feae03680654cd64c3112ce7644632c87
2015-11-19 13:42:03 -08:00
Elliott Hughes
04303f5a8a Add semaphore tests, fix sem_destroy.
Bug: https://code.google.com/p/android/issues/detail?id=76088
Change-Id: I4a0561b23e90312384d40a1c804ca64ee98f4066
2014-09-19 17:37:06 -07:00
Elliott Hughes
11952073af Remove dependencies on obsolete __ARCH_WANT_SYSCALL_DEPRECATED system calls.
(aarch64 kernels don't have these system calls.)

Change-Id: I6f64075aa412f71520f2df71c3d69b647f91c1ca
2013-10-24 15:48:32 -07:00