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dm: fix queue start/stop imbalance under suspend/load/resume races

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When suspend and load run concurrently, before q->mq_ops is set in
blk_mq_init_allocated_queue(), __dm_suspend() skip dm_stop_queue(). As a
result, the queue's quiesce depth is not incremented.

Later, once table load has finished and __dm_resume() runs, which triggers
q->quiesce_depth ==0 warning in blk_mq_unquiesce_queue():
Call Trace:
 <TASK>
 dm_start_queue+0x16/0x20 [dm_mod]
 __dm_resume+0xac/0xb0 [dm_mod]
 dm_resume+0x12d/0x150 [dm_mod]
 do_resume+0x2c2/0x420 [dm_mod]
 dev_suspend+0x30/0x130 [dm_mod]
 ctl_ioctl+0x402/0x570 [dm_mod]
 dm_ctl_ioctl+0x23/0x30 [dm_mod]

Fix this by explicitly tracking whether the request queue was
stopped in __dm_suspend() via a new DMF_QUEUE_STOPPED flag.
Only call dm_start_queue() in __dm_resume() if the queue was
actually stopped.

Fixes: e70feb8b3e ("blk-mq: support concurrent queue quiesce/unquiesce")
Cc: stable@vger.kernel.org
Signed-off-by: Zheng Qixing <zhengqixing@huawei.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
This commit is contained in:
Zheng Qixing 2025-08-26 15:42:03 +08:00 committed by Mikulas Patocka
parent 1d57628ff9
commit 7f597c2cdb
2 changed files with 6 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
drivers/md/dm-core.h
View File

@ -162,6 +162,7 @@ struct mapped_device {
#define DMF_SUSPENDED_INTERNALLY 7
#define DMF_POST_SUSPENDING 8
#define DMF_EMULATE_ZONE_APPEND 9
#define DMF_QUEUE_STOPPED 10
static inline sector_t dm_get_size(struct mapped_device *md)
{

8
drivers/md/dm.c
View File

@ -2960,8 +2960,10 @@ static int __dm_suspend(struct mapped_device *md, struct dm_table *map,
* Stop md->queue before flushing md->wq in case request-based
* dm defers requests to md->wq from md->queue.
*/
if (dm_request_based(md))
if (dm_request_based(md)) {
dm_stop_queue(md->queue);
set_bit(DMF_QUEUE_STOPPED, &md->flags);
}
flush_workqueue(md->wq);
@ -2983,7 +2985,7 @@ static int __dm_suspend(struct mapped_device *md, struct dm_table *map,
if (r < 0) {
dm_queue_flush(md);
if (dm_request_based(md))
if (test_and_clear_bit(DMF_QUEUE_STOPPED, &md->flags))
dm_start_queue(md->queue);
unlock_fs(md);
@ -3067,7 +3069,7 @@ static int __dm_resume(struct mapped_device *md, struct dm_table *map)
* so that mapping of targets can work correctly.
* Request-based dm is queueing the deferred I/Os in its request_queue.
*/
if (dm_request_based(md))
if (test_and_clear_bit(DMF_QUEUE_STOPPED, &md->flags))
dm_start_queue(md->queue);
unlock_fs(md);