From ee37e62191a59d253fc916b9fc763deb777211e2 Mon Sep 17 00:00:00 2001 From: Yufen Yu Date: Tue, 2 Apr 2019 14:22:14 +0800 Subject: [PATCH] md: add mddev->pers to avoid potential NULL pointer dereference 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 --- 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 1fa2682..664b77c 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -2850,8 +2850,10 @@ 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 -- 2.7.4