Commit 49da1910 authored by Ming Lei's avatar Ming Lei Committed by Zheng Qixing
Browse files

virtio-blk: don't keep queue frozen during system suspend 

stable inclusion
from stable-v6.6.69
commit 12c0ddd6c551c1e438b087f874b4f1223a75f7ea
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/IBJ6SJ
CVE: CVE-2024-57946
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=12c0ddd6c551c1e438b087f874b4f1223a75f7ea

--------------------------

[ Upstream commit 7678abee0867e6b7fb89aa40f6e9f575f755fb37 ]

Commit 4ce6e2db00de ("virtio-blk: Ensure no requests in virtqueues before
deleting vqs.") replaces queue quiesce with queue freeze in virtio-blk's
PM callbacks. And the motivation is to drain inflight IOs before suspending.

block layer's queue freeze looks very handy, but it is also easy to cause
deadlock, such as, any attempt to call into bio_queue_enter() may run into
deadlock if the queue is frozen in current context. There are all kinds
of ->suspend() called in suspend context, so keeping queue frozen in the
whole suspend context isn't one good idea. And Marek reported lockdep
warning[1] caused by virtio-blk's freeze queue in virtblk_freeze().

[1] https://lore.kernel.org/linux-block/ca16370e-d646-4eee-b9cc-87277c89c43c@samsung.com/



Given the motivation is to drain in-flight IOs, it can be done by calling
freeze & unfreeze, meantime restore to previous behavior by keeping queue
quiesced during suspend.

Cc: Yi Sun <yi.sun@unisoc.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Cc: virtualization@lists.linux.dev
Reported-by: default avatarMarek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
Acked-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Link: https://lore.kernel.org/r/20241112125821.1475793-1-ming.lei@redhat.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
Signed-off-by: default avatarZheng Qixing <zhengqixing@huawei.com>
parent 56e0de56

drivers/block/virtio_blk.c

+5 −2
Original line number Diff line number Diff line
@@ -1598,9 +1598,12 @@ static void virtblk_remove(struct virtio_device *vdev) 
static int virtblk_freeze(struct virtio_device *vdev)

{

	struct virtio_blk *vblk = vdev->priv;

	struct request_queue *q = vblk->disk->queue;



	/* Ensure no requests in virtqueues before deleting vqs. */

	blk_mq_freeze_queue(vblk->disk->queue);

	blk_mq_freeze_queue(q);

	blk_mq_quiesce_queue_nowait(q);

	blk_mq_unfreeze_queue(q);



	/* Ensure we don't receive any more interrupts */

	virtio_reset_device(vdev);
@@ -1624,8 +1627,8 @@ static int virtblk_restore(struct virtio_device *vdev) 
		return ret;



	virtio_device_ready(vdev);

	blk_mq_unquiesce_queue(vblk->disk->queue);



	blk_mq_unfreeze_queue(vblk->disk->queue);

	return 0;

}

#endif