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| author | Rik van Riel <riel@surriel.com> | 2025-01-28 16:35:39 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-03-22 12:56:45 -0700 |
| commit | 694fab1cf3ccd3dd0e69e3c3323e343df2dd2926 (patch) | |
| tree | e6f873814032354793cd105bfb39d9e9eda75ab1 | |
| parent | 9aedc776b11038f04f4641241bb7e877781e4aa4 (diff) | |
| download | linux-694fab1cf3ccd3dd0e69e3c3323e343df2dd2926.tar.gz linux-694fab1cf3ccd3dd0e69e3c3323e343df2dd2926.tar.bz2 linux-694fab1cf3ccd3dd0e69e3c3323e343df2dd2926.zip | |
scsi: core: Use GFP_NOIO to avoid circular locking dependency
[ Upstream commit 5363ee9d110e139584c2d92a0b640bc210588506 ]
Filesystems can write to disk from page reclaim with __GFP_FS
set. Marc found a case where scsi_realloc_sdev_budget_map() ends up in
page reclaim with GFP_KERNEL, where it could try to take filesystem
locks again, leading to a deadlock.
WARNING: possible circular locking dependency detected
6.13.0 #1 Not tainted
------------------------------------------------------
kswapd0/70 is trying to acquire lock:
ffff8881025d5d78 (&q->q_usage_counter(io)){++++}-{0:0}, at: blk_mq_submit_bio+0x461/0x6e0
but task is already holding lock:
ffffffff81ef5f40 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0x9f/0x760
The full lockdep splat can be found in Marc's report:
https://lkml.org/lkml/2025/1/24/1101
Avoid the potential deadlock by doing the allocation with GFP_NOIO, which
prevents both filesystem and block layer recursion.
Reported-by: Marc Aurèle La France <tsi@tuyoix.net>
Signed-off-by: Rik van Riel <riel@surriel.com>
Link: https://lore.kernel.org/r/20250129104525.0ae8421e@fangorn
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | drivers/scsi/scsi_scan.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c index 042329b74c6e..fe08af4dcb67 100644 --- a/drivers/scsi/scsi_scan.c +++ b/drivers/scsi/scsi_scan.c @@ -245,7 +245,7 @@ static int scsi_realloc_sdev_budget_map(struct scsi_device *sdev, } ret = sbitmap_init_node(&sdev->budget_map, scsi_device_max_queue_depth(sdev), - new_shift, GFP_KERNEL, + new_shift, GFP_NOIO, sdev->request_queue->node, false, true); if (!ret) sbitmap_resize(&sdev->budget_map, depth); |