From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sasha Levin Subject: [PATCH AUTOSEL 4.4 38/56] md: add mddev->pers to avoid potential NULL pointer dereference Date: Sat, 1 Jun 2019 09:25:42 -0400 Message-ID: <20190601132600.27427-38-sashal@kernel.org> References: <20190601132600.27427-1-sashal@kernel.org> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20190601132600.27427-1-sashal@kernel.org> Sender: linux-kernel-owner@vger.kernel.org To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Yufen Yu , Xiao Ni , NeilBrown , Song Liu , Sasha Levin , linux-raid@vger.kernel.org List-Id: linux-raid.ids From: Yufen Yu [ 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 Cc: NeilBrown Cc: # 4.4+ Reviewed-by: NeilBrown Signed-off-by: Yufen Yu Signed-off-by: Song Liu Signed-off-by: Sasha Levin --- 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 -- 2.20.1