From: Yufen Yu yuyufen@huawei.com
[ Upstream commit ee37e62191a59d253fc916b9fc763deb777211e2 ]
When doing re-add, we need to ensure rdev->mddev->pers is not NULL, which can avoid potential NULL pointer derefence in fallowing add_bound_rdev().
Fixes: a6da4ef85cef ("md: re-add a failed disk") Cc: Xiao Ni xni@redhat.com Cc: NeilBrown neilb@suse.com Cc: stable@vger.kernel.org # 4.4+ Reviewed-by: NeilBrown neilb@suse.com Signed-off-by: Yufen Yu yuyufen@huawei.com Signed-off-by: Song Liu songliubraving@fb.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/md/md.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/md/md.c b/drivers/md/md.c index 07f307402351b..f71cca28dddac 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -2690,8 +2690,10 @@ state_store(struct md_rdev *rdev, const char *buf, size_t len) err = 0; } } else if (cmd_match(buf, "re-add")) { - if (test_bit(Faulty, &rdev->flags) && (rdev->raid_disk == -1) && - rdev->saved_raid_disk >= 0) { + if (!rdev->mddev->pers) + err = -EINVAL; + else if (test_bit(Faulty, &rdev->flags) && (rdev->raid_disk == -1) && + rdev->saved_raid_disk >= 0) { /* clear_bit is performed _after_ all the devices * have their local Faulty bit cleared. If any writes * happen in the meantime in the local node, they