From: Shaohua Li Date: Tue, 15 Apr 2014 01:12:54 +0000 (+0800) Subject: raid5: fix a race of stripe count check X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=c7a6d35e463caacab08ca0333bdec5b8bdce8bbb;p=GitHub%2Fexynos8895%2Fandroid_kernel_samsung_universal8895.git 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 Signed-off-by: NeilBrown --- diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 25247a852912..ad1b9bea446e 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; }