diff options
author | jhb <jhb@FreeBSD.org> | 2015-10-06 22:28:28 +0000 |
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committer | jhb <jhb@FreeBSD.org> | 2015-10-06 22:28:28 +0000 |
commit | 08449d14c723d0140fb8b505a4782d13e5745c57 (patch) | |
tree | b782905644a30cef9fd5bc113840ff6bfaa43e0a | |
parent | fd0437ce23b03438d45c73c82578740ce79533c6 (diff) | |
download | FreeBSD-src-08449d14c723d0140fb8b505a4782d13e5745c57.zip FreeBSD-src-08449d14c723d0140fb8b505a4782d13e5745c57.tar.gz |
MFC 287833:
Threads holding a read lock of a sleepable rm lock are not permitted
to sleep. The rmlock implementation enforces this by disabling
sleeping when a read lock is acquired. To simplify the implementation,
sleeping is disabled for most of the duration of rm_rlock. However,
it doesn't need to be disabled until the lock is acquired. If a
sleepable rm lock is contested, then rm_rlock may need to acquire the
backing sx lock. This tripped the overly-broad assertion. Fix by
relaxing the assertion around the call to sx_xlock().
-rw-r--r-- | sys/kern/kern_rmlock.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/sys/kern/kern_rmlock.c b/sys/kern/kern_rmlock.c index 1ac08de..194c603 100644 --- a/sys/kern/kern_rmlock.c +++ b/sys/kern/kern_rmlock.c @@ -402,9 +402,11 @@ _rm_rlock_hard(struct rmlock *rm, struct rm_priotracker *tracker, int trylock) return (0); } } else { - if (rm->lock_object.lo_flags & LO_SLEEPABLE) + if (rm->lock_object.lo_flags & LO_SLEEPABLE) { + THREAD_SLEEPING_OK(); sx_xlock(&rm->rm_lock_sx); - else + THREAD_NO_SLEEPING(); + } else mtx_lock(&rm->rm_lock_mtx); } |