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| author | marcel <marcel@FreeBSD.org> | 2009-12-14 01:26:01 +0000 |
|---|---|---|
| committer | marcel <marcel@FreeBSD.org> | 2009-12-14 01:26:01 +0000 |
| commit | 5c1d0ca7f5cbc1565b5ce338ca1af86d3b2f5c5d (patch) | |
| tree | 42ae61d08bc1543ceffe1d63f34027181663e65b /lib/libthr/thread | |
| parent | 9d3913ddbe027b28489f24483ee9b96aafab016c (diff) | |
| download | FreeBSD-src-5c1d0ca7f5cbc1565b5ce338ca1af86d3b2f5c5d.zip FreeBSD-src-5c1d0ca7f5cbc1565b5ce338ca1af86d3b2f5c5d.tar.gz | |
Work-around a race condition on ia64 while unlocking a contested lock.
The race condition is believed to be in UMTX_OP_MUTEX_WAKE. On ia64,
we simply go to the kernel to unlock.
The big question is why this is only a race condition on ia64...
MFC after: 3 days
Diffstat (limited to 'lib/libthr/thread')
| -rw-r--r-- | lib/libthr/thread/thr_umtx.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/lib/libthr/thread/thr_umtx.c b/lib/libthr/thread/thr_umtx.c index 7c59bb7..5af923d 100644 --- a/lib/libthr/thread/thr_umtx.c +++ b/lib/libthr/thread/thr_umtx.c @@ -112,10 +112,13 @@ __thr_umutex_timedlock(struct umutex *mtx, uint32_t id, int __thr_umutex_unlock(struct umutex *mtx, uint32_t id) { +#ifndef __ia64__ + /* XXX this logic has a race-condition on ia64. */ if ((mtx->m_flags & (UMUTEX_PRIO_PROTECT | UMUTEX_PRIO_INHERIT)) == 0) { atomic_cmpset_rel_32(&mtx->m_owner, id | UMUTEX_CONTESTED, UMUTEX_CONTESTED); return _umtx_op_err(mtx, UMTX_OP_MUTEX_WAKE, 0, 0, 0); } +#endif /* __ia64__ */ return _umtx_op_err(mtx, UMTX_OP_MUTEX_UNLOCK, 0, 0, 0); } |
