From bd6919228d7e1867ae9e24ab27e3e4a366c87d21 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Thu, 25 Jun 2015 17:01:40 +1000 Subject: md: clear mddev->private when it has been freed. If ->private is set when ->run is called, it is assumed to be a 'config' prepared as part of 'reshape'. So it is important when we free that config, that we also clear ->private. This is not often a problem as the mddev will normally be discarded shortly after the config us freed. However if an 'assemble' races with a final close, the assemble can use the old mddev which has a stale ->private. This leads to any of various sorts of crashes. So clear ->private after calling ->free(). Reported-by: Nate Clark Cc: stable@vger.kernel.org (v4.0+) Fixes: afa0f557cb15 ("md: rename ->stop to ->free") Signed-off-by: NeilBrown --- drivers/md/md.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/md/md.c b/drivers/md/md.c index 3d339e283cf6..939739f0f881 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -5178,6 +5178,7 @@ int md_run(struct mddev *mddev) mddev_detach(mddev); if (mddev->private) pers->free(mddev, mddev->private); + mddev->private = NULL; module_put(pers->owner); bitmap_destroy(mddev); return err; @@ -5313,6 +5314,7 @@ static void md_clean(struct mddev *mddev) mddev->changed = 0; mddev->degraded = 0; mddev->safemode = 0; + mddev->private = NULL; mddev->merge_check_needed = 0; mddev->bitmap_info.offset = 0; mddev->bitmap_info.default_offset = 0; @@ -5385,6 +5387,7 @@ static void __md_stop(struct mddev *mddev) mddev->pers = NULL; spin_unlock(&mddev->lock); pers->free(mddev, mddev->private); + mddev->private = NULL; if (pers->sync_request && mddev->to_remove == NULL) mddev->to_remove = &md_redundancy_group; module_put(pers->owner); -- cgit v1.2.3