From 137ae5d29191831b000584e869096796f9a88213 Mon Sep 17 00:00:00 2001 From: Attilio Rao Date: Mon, 6 Jul 2009 09:31:04 +0000 Subject: [PATCH] In the current code, rdlock_count is not correctly handled for some cases. The most notable is that it is not bumped in rwlock_rdlock_common() when the hard path (__thr_rwlock_rdlock()) returns successfully. This can lead to deadlocks in libthr when rwlocks recursion in read mode happens. Fix the interested parts by correctly handling rdlock_count. PR: threads/136345 Reported by: rink Tested by: rink Reviewed by: jeff Approved by: re (kib) MFC: 2 weeks --- lib/libthr/thread/thr_rtld.c | 2 ++ lib/libthr/thread/thr_rwlock.c | 3 ++- 2 files changed, 4 insertions(+), 1 deletion(-) diff --git a/lib/libthr/thread/thr_rtld.c b/lib/libthr/thread/thr_rtld.c index 7e263401854c..4db08bd617c0 100644 --- a/lib/libthr/thread/thr_rtld.c +++ b/lib/libthr/thread/thr_rtld.c @@ -114,6 +114,7 @@ _thr_rtld_rlock_acquire(void *lock) THR_CRITICAL_ENTER(curthread); while (_thr_rwlock_rdlock(&l->lock, 0, NULL) != 0) ; + curthread->rdlock_count++; RESTORE_ERRNO(); } @@ -148,6 +149,7 @@ _thr_rtld_lock_release(void *lock) state = l->lock.rw_state; if (_thr_rwlock_unlock(&l->lock) == 0) { + curthread->rdlock_count--; if ((state & URWLOCK_WRITE_OWNER) == 0) { THR_CRITICAL_LEAVE(curthread); } else { diff --git a/lib/libthr/thread/thr_rwlock.c b/lib/libthr/thread/thr_rwlock.c index 641749b3b427..de61e51b2bf8 100644 --- a/lib/libthr/thread/thr_rwlock.c +++ b/lib/libthr/thread/thr_rwlock.c @@ -177,10 +177,11 @@ rwlock_rdlock_common(pthread_rwlock_t *rwlock, const struct timespec *abstime) /* if interrupted, try to lock it in userland again. */ if (_thr_rwlock_tryrdlock(&prwlock->lock, flags) == 0) { ret = 0; - curthread->rdlock_count++; break; } } + if (ret == 0) + curthread->rdlock_count++; return (ret); }