[syzbot] [block?] possible deadlock in blk_mq_submit_bio

syzbot
2024-11-23T15:37:22Z

Hello,

syzbot found the following issue on:

HEAD commit: 06afb0f36106 Merge tag 'trace-v6.13' of git://git.kernel.o..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=148bfec0580000
kernel config: https://syzkaller.appspot.com/x/.config?x=b011a14ee4cb9480
dashboard link: https://syzkaller.appspot.com/bug?extid=5218c85078236fc46227
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: i386

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-06afb0f3.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/aae0561fd279/vmlinux-06afb0f3.xz
kernel image: https://storage.googleapis.com/syzbot-assets/faa3af3fa7ce/bzImage-06afb0f3.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+5218c85078236fc46227@syzkaller.appspotmail.com

======================================================
WARNING: possible circular locking dependency detected
6.12.0-syzkaller-07834-g06afb0f36106 #0 Not tainted
------------------------------------------------------
kswapd0/112 is trying to acquire lock:
ffff88801f3f1438 (&q->q_usage_counter(io)#68){++++}-{0:0}, at: bio_queue_enter block/blk.h:79 [inline]
ffff88801f3f1438 (&q->q_usage_counter(io)#68){++++}-{0:0}, at: blk_mq_submit_bio+0x7ca/0x24c0 block/blk-mq.c:3092

but task is already holding lock:
ffffffff8df4de60 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0xcd9/0x18f0 mm/vmscan.c:6976

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (fs_reclaim){+.+.}-{0:0}:
__fs_reclaim_acquire mm/page_alloc.c:3851 [inline]
fs_reclaim_acquire+0x102/0x150 mm/page_alloc.c:3865
might_alloc include/linux/sched/mm.h:318 [inline]
slab_pre_alloc_hook mm/slub.c:4036 [inline]
slab_alloc_node mm/slub.c:4114 [inline]
__do_kmalloc_node mm/slub.c:4263 [inline]
__kmalloc_node_noprof+0xb7/0x440 mm/slub.c:4270
__kvmalloc_node_noprof+0xad/0x1a0 mm/util.c:658
sbitmap_init_node+0x1ca/0x770 lib/sbitmap.c:132
scsi_realloc_sdev_budget_map+0x2c7/0x610 drivers/scsi/scsi_scan.c:246
scsi_add_lun+0x11b4/0x1fd0 drivers/scsi/scsi_scan.c:1106
scsi_probe_and_add_lun+0x4fa/0xda0 drivers/scsi/scsi_scan.c:1287
__scsi_add_device+0x24b/0x290 drivers/scsi/scsi_scan.c:1622
ata_scsi_scan_host+0x215/0x780 drivers/ata/libata-scsi.c:4575
async_run_entry_fn+0x9c/0x530 kernel/async.c:129
process_one_work+0x958/0x1b30 kernel/workqueue.c:3229
process_scheduled_works kernel/workqueue.c:3310 [inline]
worker_thread+0x6c8/0xf00 kernel/workqueue.c:3391
kthread+0x2c1/0x3a0 kernel/kthread.c:389
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

-> #0 (&q->q_usage_counter(io)#68){++++}-{0:0}:
check_prev_add kernel/locking/lockdep.c:3161 [inline]
check_prevs_add kernel/locking/lockdep.c:3280 [inline]
validate_chain kernel/locking/lockdep.c:3904 [inline]
__lock_acquire+0x249e/0x3c40 kernel/locking/lockdep.c:5226
lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849
__bio_queue_enter+0x4c6/0x740 block/blk-core.c:361
bio_queue_enter block/blk.h:79 [inline]
blk_mq_submit_bio+0x7ca/0x24c0 block/blk-mq.c:3092
__submit_bio+0x384/0x540 block/blk-core.c:629
__submit_bio_noacct_mq block/blk-core.c:710 [inline]
submit_bio_noacct_nocheck+0x698/0xd70 block/blk-core.c:739
submit_bio_noacct+0x93a/0x1e20 block/blk-core.c:868
swap_writepage_bdev_async mm/page_io.c:449 [inline]
__swap_writepage+0x3a3/0xf50 mm/page_io.c:472
swap_writepage+0x403/0x1040 mm/page_io.c:288
pageout+0x3b2/0xaa0 mm/vmscan.c:689
shrink_folio_list+0x3025/0x42d0 mm/vmscan.c:1367
evict_folios+0x6d6/0x1970 mm/vmscan.c:4589
try_to_shrink_lruvec+0x612/0x9b0 mm/vmscan.c:4784
shrink_one+0x3e3/0x7b0 mm/vmscan.c:4822
shrink_many mm/vmscan.c:4885 [inline]
lru_gen_shrink_node mm/vmscan.c:4963 [inline]
shrink_node+0xbbc/0x3ed0 mm/vmscan.c:5943
kswapd_shrink_node mm/vmscan.c:6771 [inline]
balance_pgdat+0xc1f/0x18f0 mm/vmscan.c:6963
kswapd+0x5f8/0xc30 mm/vmscan.c:7232
kthread+0x2c1/0x3a0 kernel/kthread.c:389
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

other info that might help us debug this:

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(fs_reclaim);
lock(&q->q_usage_counter(io)#68);
lock(fs_reclaim);
rlock(&q->q_usage_counter(io)#68);

*** DEADLOCK ***

1 lock held by kswapd0/112:
#0: ffffffff8df4de60 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0xcd9/0x18f0 mm/vmscan.c:6976

stack backtrace:
CPU: 3 UID: 0 PID: 112 Comm: kswapd0 Not tainted 6.12.0-syzkaller-07834-g06afb0f36106 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
print_circular_bug+0x41c/0x610 kernel/locking/lockdep.c:2074
check_noncircular+0x31a/0x400 kernel/locking/lockdep.c:2206
check_prev_add kernel/locking/lockdep.c:3161 [inline]
check_prevs_add kernel/locking/lockdep.c:3280 [inline]
validate_chain kernel/locking/lockdep.c:3904 [inline]
__lock_acquire+0x249e/0x3c40 kernel/locking/lockdep.c:5226
lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849
__bio_queue_enter+0x4c6/0x740 block/blk-core.c:361
bio_queue_enter block/blk.h:79 [inline]
blk_mq_submit_bio+0x7ca/0x24c0 block/blk-mq.c:3092
__submit_bio+0x384/0x540 block/blk-core.c:629
__submit_bio_noacct_mq block/blk-core.c:710 [inline]
submit_bio_noacct_nocheck+0x698/0xd70 block/blk-core.c:739
submit_bio_noacct+0x93a/0x1e20 block/blk-core.c:868
swap_writepage_bdev_async mm/page_io.c:449 [inline]
__swap_writepage+0x3a3/0xf50 mm/page_io.c:472
swap_writepage+0x403/0x1040 mm/page_io.c:288
pageout+0x3b2/0xaa0 mm/vmscan.c:689
shrink_folio_list+0x3025/0x42d0 mm/vmscan.c:1367
evict_folios+0x6d6/0x1970 mm/vmscan.c:4589
try_to_shrink_lruvec+0x612/0x9b0 mm/vmscan.c:4784
shrink_one+0x3e3/0x7b0 mm/vmscan.c:4822
shrink_many mm/vmscan.c:4885 [inline]
lru_gen_shrink_node mm/vmscan.c:4963 [inline]
shrink_node+0xbbc/0x3ed0 mm/vmscan.c:5943
kswapd_shrink_node mm/vmscan.c:6771 [inline]
balance_pgdat+0xc1f/0x18f0 mm/vmscan.c:6963
kswapd+0x5f8/0xc30 mm/vmscan.c:7232
kthread+0x2c1/0x3a0 kernel/kthread.c:389
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>

---
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