From 08449d14c723d0140fb8b505a4782d13e5745c57 Mon Sep 17 00:00:00 2001 From: jhb Date: Tue, 6 Oct 2015 22:28:28 +0000 Subject: 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(). --- sys/kern/kern_rmlock.c | 6 ++++-- 1 file 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); } -- cgit v1.1