Commit ee37e621 authored Apr 02, 2019 by Yufen Yu Committed by Song Liu Apr 10, 2019

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: a6da4ef8 ("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>

parent 0d413829

drivers/md/md.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -2850,7 +2850,9 @@ 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) &&
		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

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