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| author | Sheng Yong <shengyong1@xiaomi.com> | 2025-07-10 14:48:55 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-07-24 08:56:22 +0200 |
| commit | 68860d1ade385eef9fcdbf6552f061283091fdb8 (patch) | |
| tree | a161aece42099d60b9491f7e872e40a68f60f027 /drivers | |
| parent | 0758f7ef402b6e31c71b75b0c4aaccac3014851b (diff) | |
| download | linux-68860d1ade385eef9fcdbf6552f061283091fdb8.tar.gz linux-68860d1ade385eef9fcdbf6552f061283091fdb8.tar.bz2 linux-68860d1ade385eef9fcdbf6552f061283091fdb8.zip | |
dm-bufio: fix sched in atomic context
commit b1bf1a782fdf5c482215c0c661b5da98b8e75773 upstream.
If "try_verify_in_tasklet" is set for dm-verity, DM_BUFIO_CLIENT_NO_SLEEP
is enabled for dm-bufio. However, when bufio tries to evict buffers, there
is a chance to trigger scheduling in spin_lock_bh, the following warning
is hit:
BUG: sleeping function called from invalid context at drivers/md/dm-bufio.c:2745
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 123, name: kworker/2:2
preempt_count: 201, expected: 0
RCU nest depth: 0, expected: 0
4 locks held by kworker/2:2/123:
#0: ffff88800a2d1548 ((wq_completion)dm_bufio_cache){....}-{0:0}, at: process_one_work+0xe46/0x1970
#1: ffffc90000d97d20 ((work_completion)(&dm_bufio_replacement_work)){....}-{0:0}, at: process_one_work+0x763/0x1970
#2: ffffffff8555b528 (dm_bufio_clients_lock){....}-{3:3}, at: do_global_cleanup+0x1ce/0x710
#3: ffff88801d5820b8 (&c->spinlock){....}-{2:2}, at: do_global_cleanup+0x2a5/0x710
Preemption disabled at:
[<0000000000000000>] 0x0
CPU: 2 UID: 0 PID: 123 Comm: kworker/2:2 Not tainted 6.16.0-rc3-g90548c634bd0 #305 PREEMPT(voluntary)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
Workqueue: dm_bufio_cache do_global_cleanup
Call Trace:
<TASK>
dump_stack_lvl+0x53/0x70
__might_resched+0x360/0x4e0
do_global_cleanup+0x2f5/0x710
process_one_work+0x7db/0x1970
worker_thread+0x518/0xea0
kthread+0x359/0x690
ret_from_fork+0xf3/0x1b0
ret_from_fork_asm+0x1a/0x30
</TASK>
That can be reproduced by:
veritysetup format --data-block-size=4096 --hash-block-size=4096 /dev/vda /dev/vdb
SIZE=$(blockdev --getsz /dev/vda)
dmsetup create myverity -r --table "0 $SIZE verity 1 /dev/vda /dev/vdb 4096 4096 <data_blocks> 1 sha256 <root_hash> <salt> 1 try_verify_in_tasklet"
mount /dev/dm-0 /mnt -o ro
echo 102400 > /sys/module/dm_bufio/parameters/max_cache_size_bytes
[read files in /mnt]
Cc: stable@vger.kernel.org # v6.4+
Fixes: 450e8dee51aa ("dm bufio: improve concurrent IO performance")
Signed-off-by: Wang Shuai <wangshuai12@xiaomi.com>
Signed-off-by: Sheng Yong <shengyong1@xiaomi.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/md/dm-bufio.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c index ca60ef209df8..aaa21fe295f2 100644 --- a/drivers/md/dm-bufio.c +++ b/drivers/md/dm-bufio.c @@ -2741,7 +2741,11 @@ static unsigned long __evict_many(struct dm_bufio_client *c, __make_buffer_clean(b); __free_buffer_wake(b); - cond_resched(); + if (need_resched()) { + dm_bufio_unlock(c); + cond_resched(); + dm_bufio_lock(c); + } } return count; |