From 7639c9be4501363183b223185951e1f088076a0d Mon Sep 17 00:00:00 2001 From: Lawrence Stewart Date: Fri, 24 May 2013 00:49:12 +0000 Subject: [PATCH] Ensure alq's shutdown_pre_sync event handler is deregistered on module unload to avoid a dangling pointer and eventual panic on system shutdown. Reported by: Ali Tested by: Ali MFC after: 1 week --- sys/kern/kern_alq.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/sys/kern/kern_alq.c b/sys/kern/kern_alq.c index 893d2f83ee30..daf4e4644667 100644 --- a/sys/kern/kern_alq.c +++ b/sys/kern/kern_alq.c @@ -99,6 +99,7 @@ static LIST_HEAD(, alq) ald_active; static int ald_shutingdown = 0; struct thread *ald_thread; static struct proc *ald_proc; +static eventhandler_tag alq_eventhandler_tag = NULL; #define ALD_LOCK() mtx_lock(&ald_mtx) #define ALD_UNLOCK() mtx_unlock(&ald_mtx) @@ -194,8 +195,8 @@ ald_daemon(void) ald_thread = FIRST_THREAD_IN_PROC(ald_proc); - EVENTHANDLER_REGISTER(shutdown_pre_sync, ald_shutdown, NULL, - SHUTDOWN_PRI_FIRST); + alq_eventhandler_tag = EVENTHANDLER_REGISTER(shutdown_pre_sync, + ald_shutdown, NULL, SHUTDOWN_PRI_FIRST); ALD_LOCK(); @@ -228,6 +229,8 @@ ald_shutdown(void *arg, int howto) { struct alq *alq; + EVENTHANDLER_DEREGISTER(shutdown_pre_sync, alq_eventhandler_tag); + ALD_LOCK(); /* Ensure no new queues can be created. */