| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.1 188/267] md: clear mddev->private when it has been freed. | Date | Fri, 31 Jul 2015 12:40:39 -0700 |
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4.1-stable review patch. If anyone has any objections, please let me know.
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From: NeilBrown <neilb@suse.de>
commit bd6919228d7e1867ae9e24ab27e3e4a366c87d21 upstream.
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 <nate@neworld.us> Fixes: afa0f557cb15 ("md: rename ->stop to ->free") Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/md/md.c | 3 +++ 1 file changed, 3 insertions(+)
--- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -5159,6 +5159,7 @@ 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; @@ -5294,6 +5295,7 @@ 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; @@ -5366,6 +5368,7 @@ static void __md_stop(struct mddev *mdde 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);
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