From c7a6d35e463caacab08ca0333bdec5b8bdce8bbb Mon Sep 17 00:00:00 2001 From: Shaohua Li <shli@kernel.org> Date: Tue, 15 Apr 2014 09:12:54 +0800 Subject: [PATCH] raid5: fix a race of stripe count check I hit another BUG_ON with e240c1839d11152b0355442. In __get_priority_stripe(), stripe count equals to 0 initially. Between atomic_inc and BUG_ON, get_active_stripe() finds the stripe. So the stripe count isn't 1 any more. V2: keeps the BUG_ON suggested by Neil. Signed-off-by: Shaohua Li <shli@fusionio.com> Signed-off-by: NeilBrown <neilb@suse.de> --- drivers/md/raid5.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 25247a8529124f..ad1b9bea446ebd 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -4370,8 +4370,7 @@ static struct stripe_head *__get_priority_stripe(struct r5conf *conf, int group) sh->group = NULL; } list_del_init(&sh->lru); - atomic_inc(&sh->count); - BUG_ON(atomic_read(&sh->count) != 1); + BUG_ON(atomic_inc_return(&sh->count) != 1); return sh; } -- GitLab