4.1-stable review patch. If anyone has any objections, please let me know.
------------------
From: NeilBrown <ne...@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 <n...@neworld.us>
Fixes: afa0f557cb15 ("md: rename ->stop to ->free")
Signed-off-by: NeilBrown <ne...@suse.com>
Signed-off-by: Greg Kroah-Hartman <gre...@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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