From 2d8f613160ed303f5fe310f21bba334a4b074fa5 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Tue, 22 Aug 2006 21:22:13 +0400 Subject: [PATCH] elv_unregister: fix possible crash on module unload An exiting task or process which didn't do I/O yet have no io context, elv_unregister() should check it is not NULL. Signed-off-by: Oleg Nesterov Acked-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- block/elevator.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/block/elevator.c b/block/elevator.c index bc7baeec0d10..9b72dc7c8a5c 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -765,7 +765,8 @@ void elv_unregister(struct elevator_type *e) read_lock(&tasklist_lock); do_each_thread(g, p) { task_lock(p); - e->ops.trim(p->io_context); + if (p->io_context) + e->ops.trim(p->io_context); task_unlock(p); } while_each_thread(g, p); read_unlock(&tasklist_lock); -- 2.20.1