From 140234b2380ffb8ffb0cfc46fee0e822f43adef7 Mon Sep 17 00:00:00 2001 From: Martin Wilck Date: Thu, 23 Jul 2026 13:27:41 +0200 Subject: [PATCH] md/raid1: create serial pool adding rdev to array with serialize_policy=1 The following bug has been observed with kernel 7.1.3 after adding a new rdev to an existing RAID1 array with serialize_policy enabled: Oops: 0002 [#1] CPU: 0 UID: 0 PID: 19639 Comm: ext4lazyinit Not tainted 7.1.3-1-default RIP: _raw_spin_lock_irqsave+0x27/0x50 CR2: 0000000000004960 Call Trace: wait_for_serialization+0xb9/0x260 [raid1] raid1_make_request+0x762/0xaff [raid1] md_handle_request+0x1c9/0x2e0 [md_mod] The raid1.c code calls wait_for_serialization() if the MD_SERIALIZE_POLICY is set, and wait_for_serialization assumes that rdev->serial is initialized. Normally this will be the case for arrays that have the serialize_policy sysfs attribute set to 1. But when a new rdev is added to an existing array in bind_rdev_to_array(), the condition at mddev_create_serial_pool() causes creation of rdev->serial to be skipped. Fix it. Fixes: 69b00b5bb235 ("md: introduce a new struct for IO serialization") Signed-off-by: Martin Wilck Reviewed-by: Mykola Marzhan Link: https://patch.msgid.link/20260723112741.1206836-1-mwilck@suse.com Signed-off-by: Yu Kuai --- drivers/md/md.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/md/md.c b/drivers/md/md.c index f280664a8b32..51b620edbef7 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -235,7 +235,8 @@ void mddev_create_serial_pool(struct mddev *mddev, struct md_rdev *rdev) int ret = 0; unsigned int noio_flags; - if (rdev && !rdev_need_serial(rdev) && + if (!test_bit(MD_SERIALIZE_POLICY, &mddev->flags) && + rdev && !rdev_need_serial(rdev) && !test_bit(CollisionCheck, &rdev->flags)) return;