* [syzbot] [block?] possible deadlock in blk_mq_update_nr_hw_queues
@ 2024-11-24 23:13 syzbot
2025-04-03 19:36 ` syzbot
2025-07-13 12:20 ` syzbot
0 siblings, 2 replies; 3+ messages in thread
From: syzbot @ 2024-11-24 23:13 UTC (permalink / raw)
To: axboe, linux-block, linux-kernel, syzkaller-bugs
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=168001c0580000
kernel config: https://syzkaller.appspot.com/x/.config?x=95b76860fd16c857
dashboard link: https://syzkaller.appspot.com/bug?extid=6279b273d888c2017726
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/112cedff0255/disk-06afb0f3.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f65020d28328/vmlinux-06afb0f3.xz
kernel image: https://storage.googleapis.com/syzbot-assets/4fb4cb7df5b1/bzImage-06afb0f3.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+6279b273d888c2017726@syzkaller.appspotmail.com
======================================================
WARNING: possible circular locking dependency detected
6.12.0-syzkaller-07834-g06afb0f36106 #0 Not tainted
------------------------------------------------------
syz.2.2220/13838 is trying to acquire lock:
ffff8880257485d8 (&q->sysfs_lock){+.+.}-{4:4}, at: blk_mq_elv_switch_none block/blk-mq.c:4847 [inline]
ffff8880257485d8 (&q->sysfs_lock){+.+.}-{4:4}, at: __blk_mq_update_nr_hw_queues block/blk-mq.c:4925 [inline]
ffff8880257485d8 (&q->sysfs_lock){+.+.}-{4:4}, at: blk_mq_update_nr_hw_queues+0x3fa/0x1ae0 block/blk-mq.c:4985
but task is already holding lock:
ffff8880257480a8 (&q->q_usage_counter(io)#51){++++}-{0:0}, at: nbd_start_device+0x16c/0xaa0 drivers/block/nbd.c:1413
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #7 (&q->q_usage_counter(io)#51){++++}-{0:0}:
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
bio_queue_enter block/blk.h:75 [inline]
blk_mq_submit_bio+0x1536/0x23a0 block/blk-mq.c:3092
__submit_bio+0x2c6/0x560 block/blk-core.c:629
__submit_bio_noacct_mq block/blk-core.c:710 [inline]
submit_bio_noacct_nocheck+0x4d3/0xe30 block/blk-core.c:739
submit_bh fs/buffer.c:2824 [inline]
block_read_full_folio+0x93b/0xcd0 fs/buffer.c:2451
filemap_read_folio+0x14d/0x630 mm/filemap.c:2367
filemap_update_page mm/filemap.c:2451 [inline]
filemap_get_pages+0x17af/0x2540 mm/filemap.c:2572
filemap_read+0x45c/0xf50 mm/filemap.c:2647
blkdev_read_iter+0x2d8/0x430 block/fops.c:767
new_sync_read fs/read_write.c:484 [inline]
vfs_read+0x993/0xb70 fs/read_write.c:565
ksys_read+0x18f/0x2b0 fs/read_write.c:708
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #6 (mapping.invalidate_lock#2){++++}-{4:4}:
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
down_read+0xb1/0xa40 kernel/locking/rwsem.c:1524
filemap_invalidate_lock_shared include/linux/fs.h:873 [inline]
filemap_fault+0xd54/0x1950 mm/filemap.c:3352
__do_fault+0x137/0x460 mm/memory.c:4882
do_read_fault mm/memory.c:5297 [inline]
do_fault mm/memory.c:5431 [inline]
do_pte_missing mm/memory.c:3965 [inline]
handle_pte_fault+0x2d1c/0x6820 mm/memory.c:5766
__handle_mm_fault mm/memory.c:5909 [inline]
handle_mm_fault+0x1106/0x1bb0 mm/memory.c:6077
faultin_page mm/gup.c:1187 [inline]
__get_user_pages+0x1c82/0x49e0 mm/gup.c:1485
populate_vma_page_range+0x264/0x330 mm/gup.c:1923
__mm_populate+0x27a/0x460 mm/gup.c:2026
do_mlock+0x61f/0x7e0 mm/mlock.c:653
__do_sys_mlock mm/mlock.c:661 [inline]
__se_sys_mlock mm/mlock.c:659 [inline]
__x64_sys_mlock+0x60/0x70 mm/mlock.c:659
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #5 (&mm->mmap_lock){++++}-{4:4}:
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
__might_fault+0xc6/0x120 mm/memory.c:6716
_copy_from_iter+0x114/0x1e70 lib/iov_iter.c:259
copy_from_iter include/linux/uio.h:219 [inline]
copy_from_iter_full include/linux/uio.h:236 [inline]
skb_do_copy_data_nocache include/net/sock.h:2187 [inline]
skb_copy_to_page_nocache include/net/sock.h:2213 [inline]
tcp_sendmsg_locked+0x18a5/0x4f30 net/ipv4/tcp.c:1222
tcp_sendmsg+0x30/0x50 net/ipv4/tcp.c:1358
sock_sendmsg_nosec net/socket.c:711 [inline]
__sock_sendmsg+0x1a6/0x270 net/socket.c:726
sock_write_iter+0x2d7/0x3f0 net/socket.c:1147
new_sync_write fs/read_write.c:586 [inline]
vfs_write+0xaed/0xd30 fs/read_write.c:679
ksys_write+0x18f/0x2b0 fs/read_write.c:731
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #4 (sk_lock-AF_INET){+.+.}-{0:0}:
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
lock_sock_nested+0x48/0x100 net/core/sock.c:3622
lock_sock include/net/sock.h:1617 [inline]
inet_autobind net/ipv4/af_inet.c:178 [inline]
inet_send_prepare net/ipv4/af_inet.c:837 [inline]
inet_sendmsg+0x120/0x390 net/ipv4/af_inet.c:848
sock_sendmsg_nosec net/socket.c:711 [inline]
__sock_sendmsg+0x1a6/0x270 net/socket.c:726
sock_sendmsg+0x134/0x200 net/socket.c:749
__sock_xmit+0x219/0x4e0 drivers/block/nbd.c:577
sock_xmit drivers/block/nbd.c:605 [inline]
nbd_send_cmd drivers/block/nbd.c:691 [inline]
nbd_handle_cmd drivers/block/nbd.c:1113 [inline]
nbd_queue_rq+0x163c/0x2f30 drivers/block/nbd.c:1143
blk_mq_dispatch_rq_list+0xad5/0x19d0 block/blk-mq.c:2120
__blk_mq_do_dispatch_sched block/blk-mq-sched.c:170 [inline]
blk_mq_do_dispatch_sched block/blk-mq-sched.c:184 [inline]
__blk_mq_sched_dispatch_requests+0xb8a/0x1840 block/blk-mq-sched.c:309
blk_mq_sched_dispatch_requests+0xd6/0x190 block/blk-mq-sched.c:331
blk_mq_run_hw_queue+0x354/0x500 block/blk-mq.c:2354
blk_mq_flush_plug_list+0x118e/0x1870 block/blk-mq.c:2915
__blk_flush_plug+0x420/0x500 block/blk-core.c:1213
blk_finish_plug block/blk-core.c:1240 [inline]
__submit_bio+0x46a/0x560 block/blk-core.c:637
__submit_bio_noacct_mq block/blk-core.c:710 [inline]
submit_bio_noacct_nocheck+0x4d3/0xe30 block/blk-core.c:739
submit_bh fs/buffer.c:2824 [inline]
block_read_full_folio+0x93b/0xcd0 fs/buffer.c:2451
filemap_read_folio+0x14d/0x630 mm/filemap.c:2367
do_read_cache_folio+0x3f5/0x850 mm/filemap.c:3827
read_mapping_folio include/linux/pagemap.h:1011 [inline]
read_part_sector+0xb3/0x330 block/partitions/core.c:722
adfspart_check_ICS+0xd9/0x9a0 block/partitions/acorn.c:360
check_partition block/partitions/core.c:141 [inline]
blk_add_partitions block/partitions/core.c:589 [inline]
bdev_disk_changed+0x72e/0x13f0 block/partitions/core.c:693
blkdev_get_whole+0x2d2/0x450 block/bdev.c:707
bdev_open+0x2d4/0xc50 block/bdev.c:916
blkdev_open+0x389/0x4f0 block/fops.c:627
do_dentry_open+0xbe3/0x1b70 fs/open.c:945
vfs_open+0x3e/0x330 fs/open.c:1075
do_open fs/namei.c:3828 [inline]
path_openat+0x2c84/0x3590 fs/namei.c:3987
do_filp_open+0x27f/0x4e0 fs/namei.c:4014
do_sys_openat2+0x13e/0x1d0 fs/open.c:1402
do_sys_open fs/open.c:1417 [inline]
__do_sys_openat fs/open.c:1433 [inline]
__se_sys_openat fs/open.c:1428 [inline]
__x64_sys_openat+0x247/0x2a0 fs/open.c:1428
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #3 (&nsock->tx_lock){+.+.}-{4:4}:
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
__mutex_lock_common kernel/locking/mutex.c:585 [inline]
__mutex_lock+0x1ac/0xee0 kernel/locking/mutex.c:735
nbd_handle_cmd drivers/block/nbd.c:1079 [inline]
nbd_queue_rq+0x29c/0x2f30 drivers/block/nbd.c:1143
blk_mq_dispatch_rq_list+0xad5/0x19d0 block/blk-mq.c:2120
__blk_mq_do_dispatch_sched block/blk-mq-sched.c:170 [inline]
blk_mq_do_dispatch_sched block/blk-mq-sched.c:184 [inline]
__blk_mq_sched_dispatch_requests+0xb8a/0x1840 block/blk-mq-sched.c:309
blk_mq_sched_dispatch_requests+0xd6/0x190 block/blk-mq-sched.c:331
blk_mq_run_hw_queue+0x354/0x500 block/blk-mq.c:2354
blk_mq_flush_plug_list+0x118e/0x1870 block/blk-mq.c:2915
__blk_flush_plug+0x420/0x500 block/blk-core.c:1213
blk_finish_plug block/blk-core.c:1240 [inline]
__submit_bio+0x46a/0x560 block/blk-core.c:637
__submit_bio_noacct_mq block/blk-core.c:710 [inline]
submit_bio_noacct_nocheck+0x4d3/0xe30 block/blk-core.c:739
submit_bh fs/buffer.c:2824 [inline]
block_read_full_folio+0x93b/0xcd0 fs/buffer.c:2451
filemap_read_folio+0x14d/0x630 mm/filemap.c:2367
do_read_cache_folio+0x3f5/0x850 mm/filemap.c:3827
read_mapping_folio include/linux/pagemap.h:1011 [inline]
read_part_sector+0xb3/0x330 block/partitions/core.c:722
adfspart_check_ICS+0xd9/0x9a0 block/partitions/acorn.c:360
check_partition block/partitions/core.c:141 [inline]
blk_add_partitions block/partitions/core.c:589 [inline]
bdev_disk_changed+0x72e/0x13f0 block/partitions/core.c:693
blkdev_get_whole+0x2d2/0x450 block/bdev.c:707
bdev_open+0x2d4/0xc50 block/bdev.c:916
blkdev_open+0x389/0x4f0 block/fops.c:627
do_dentry_open+0xbe3/0x1b70 fs/open.c:945
vfs_open+0x3e/0x330 fs/open.c:1075
do_open fs/namei.c:3828 [inline]
path_openat+0x2c84/0x3590 fs/namei.c:3987
do_filp_open+0x27f/0x4e0 fs/namei.c:4014
do_sys_openat2+0x13e/0x1d0 fs/open.c:1402
do_sys_open fs/open.c:1417 [inline]
__do_sys_openat fs/open.c:1433 [inline]
__se_sys_openat fs/open.c:1428 [inline]
__x64_sys_openat+0x247/0x2a0 fs/open.c:1428
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #2 (&cmd->lock){+.+.}-{4:4}:
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
__mutex_lock_common kernel/locking/mutex.c:585 [inline]
__mutex_lock+0x1ac/0xee0 kernel/locking/mutex.c:735
nbd_queue_rq+0xfe/0x2f30 drivers/block/nbd.c:1135
blk_mq_dispatch_rq_list+0xad5/0x19d0 block/blk-mq.c:2120
__blk_mq_do_dispatch_sched block/blk-mq-sched.c:170 [inline]
blk_mq_do_dispatch_sched block/blk-mq-sched.c:184 [inline]
__blk_mq_sched_dispatch_requests+0xb8a/0x1840 block/blk-mq-sched.c:309
blk_mq_sched_dispatch_requests+0xd6/0x190 block/blk-mq-sched.c:331
blk_mq_run_hw_queue+0x354/0x500 block/blk-mq.c:2354
blk_mq_flush_plug_list+0x118e/0x1870 block/blk-mq.c:2915
__blk_flush_plug+0x420/0x500 block/blk-core.c:1213
blk_finish_plug block/blk-core.c:1240 [inline]
__submit_bio+0x46a/0x560 block/blk-core.c:637
__submit_bio_noacct_mq block/blk-core.c:710 [inline]
submit_bio_noacct_nocheck+0x4d3/0xe30 block/blk-core.c:739
submit_bh fs/buffer.c:2824 [inline]
block_read_full_folio+0x93b/0xcd0 fs/buffer.c:2451
filemap_read_folio+0x14d/0x630 mm/filemap.c:2367
do_read_cache_folio+0x3f5/0x850 mm/filemap.c:3827
read_mapping_folio include/linux/pagemap.h:1011 [inline]
read_part_sector+0xb3/0x330 block/partitions/core.c:722
adfspart_check_ICS+0xd9/0x9a0 block/partitions/acorn.c:360
check_partition block/partitions/core.c:141 [inline]
blk_add_partitions block/partitions/core.c:589 [inline]
bdev_disk_changed+0x72e/0x13f0 block/partitions/core.c:693
blkdev_get_whole+0x2d2/0x450 block/bdev.c:707
bdev_open+0x2d4/0xc50 block/bdev.c:916
blkdev_open+0x389/0x4f0 block/fops.c:627
do_dentry_open+0xbe3/0x1b70 fs/open.c:945
vfs_open+0x3e/0x330 fs/open.c:1075
do_open fs/namei.c:3828 [inline]
path_openat+0x2c84/0x3590 fs/namei.c:3987
do_filp_open+0x27f/0x4e0 fs/namei.c:4014
do_sys_openat2+0x13e/0x1d0 fs/open.c:1402
do_sys_open fs/open.c:1417 [inline]
__do_sys_openat fs/open.c:1433 [inline]
__se_sys_openat fs/open.c:1428 [inline]
__x64_sys_openat+0x247/0x2a0 fs/open.c:1428
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #1 (set->srcu){.+.+}-{0:0}:
lock_sync+0x18b/0x310 kernel/locking/lockdep.c:5897
srcu_lock_sync include/linux/srcu.h:170 [inline]
__synchronize_srcu+0xb1/0x400 kernel/rcu/srcutree.c:1418
elevator_disable+0x8c/0x3f0 block/elevator.c:671
blk_mq_elv_switch_none block/blk-mq.c:4861 [inline]
__blk_mq_update_nr_hw_queues block/blk-mq.c:4925 [inline]
blk_mq_update_nr_hw_queues+0x646/0x1ae0 block/blk-mq.c:4985
nbd_start_device+0x16c/0xaa0 drivers/block/nbd.c:1413
nbd_start_device_ioctl drivers/block/nbd.c:1464 [inline]
__nbd_ioctl drivers/block/nbd.c:1539 [inline]
nbd_ioctl+0x5dc/0xf40 drivers/block/nbd.c:1579
blkdev_ioctl+0x57f/0x6a0 block/ioctl.c:693
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:906 [inline]
__se_sys_ioctl+0xf7/0x170 fs/ioctl.c:892
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #0 (&q->sysfs_lock){+.+.}-{4:4}:
check_prev_add kernel/locking/lockdep.c:3161 [inline]
check_prevs_add kernel/locking/lockdep.c:3280 [inline]
validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904
__lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5226
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
__mutex_lock_common kernel/locking/mutex.c:585 [inline]
__mutex_lock+0x1ac/0xee0 kernel/locking/mutex.c:735
blk_mq_elv_switch_none block/blk-mq.c:4847 [inline]
__blk_mq_update_nr_hw_queues block/blk-mq.c:4925 [inline]
blk_mq_update_nr_hw_queues+0x3fa/0x1ae0 block/blk-mq.c:4985
nbd_start_device+0x16c/0xaa0 drivers/block/nbd.c:1413
nbd_start_device_ioctl drivers/block/nbd.c:1464 [inline]
__nbd_ioctl drivers/block/nbd.c:1539 [inline]
nbd_ioctl+0x5dc/0xf40 drivers/block/nbd.c:1579
blkdev_ioctl+0x57f/0x6a0 block/ioctl.c:693
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:906 [inline]
__se_sys_ioctl+0xf7/0x170 fs/ioctl.c:892
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
other info that might help us debug this:
Chain exists of:
&q->sysfs_lock --> mapping.invalidate_lock#2 --> &q->q_usage_counter(io)#51
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&q->q_usage_counter(io)#51);
lock(mapping.invalidate_lock#2);
lock(&q->q_usage_counter(io)#51);
lock(&q->sysfs_lock);
*** DEADLOCK ***
4 locks held by syz.2.2220/13838:
#0: ffff8880256d9198 (&nbd->config_lock){+.+.}-{4:4}, at: nbd_ioctl+0x13c/0xf40 drivers/block/nbd.c:1572
#1: ffff8880256d90d8 (&set->tag_list_lock){+.+.}-{4:4}, at: blk_mq_update_nr_hw_queues+0xc2/0x1ae0 block/blk-mq.c:4984
#2: ffff8880257480a8 (&q->q_usage_counter(io)#51){++++}-{0:0}, at: nbd_start_device+0x16c/0xaa0 drivers/block/nbd.c:1413
#3: ffff8880257480e0 (&q->q_usage_counter(queue)#35){+.+.}-{0:0}, at: nbd_start_device+0x16c/0xaa0 drivers/block/nbd.c:1413
stack backtrace:
CPU: 0 UID: 0 PID: 13838 Comm: syz.2.2220 Not tainted 6.12.0-syzkaller-07834-g06afb0f36106 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2074
check_noncircular+0x36a/0x4a0 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+0x18ef/0x5920 kernel/locking/lockdep.c:3904
__lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5226
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
__mutex_lock_common kernel/locking/mutex.c:585 [inline]
__mutex_lock+0x1ac/0xee0 kernel/locking/mutex.c:735
blk_mq_elv_switch_none block/blk-mq.c:4847 [inline]
__blk_mq_update_nr_hw_queues block/blk-mq.c:4925 [inline]
blk_mq_update_nr_hw_queues+0x3fa/0x1ae0 block/blk-mq.c:4985
nbd_start_device+0x16c/0xaa0 drivers/block/nbd.c:1413
nbd_start_device_ioctl drivers/block/nbd.c:1464 [inline]
__nbd_ioctl drivers/block/nbd.c:1539 [inline]
nbd_ioctl+0x5dc/0xf40 drivers/block/nbd.c:1579
blkdev_ioctl+0x57f/0x6a0 block/ioctl.c:693
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:906 [inline]
__se_sys_ioctl+0xf7/0x170 fs/ioctl.c:892
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1bdd97e819
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f1bde6e7038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f1bddb35fa0 RCX: 00007f1bdd97e819
RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000003
RBP: 00007f1bdd9f175e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f1bddb35fa0 R15: 00007ffeb92d6118
</TASK>
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [syzbot] [block?] possible deadlock in blk_mq_update_nr_hw_queues
2024-11-24 23:13 [syzbot] [block?] possible deadlock in blk_mq_update_nr_hw_queues syzbot
@ 2025-04-03 19:36 ` syzbot
2025-07-13 12:20 ` syzbot
1 sibling, 0 replies; 3+ messages in thread
From: syzbot @ 2025-04-03 19:36 UTC (permalink / raw)
To: axboe, linux-block, linux-kernel, syzkaller-bugs
syzbot has found a reproducer for the following issue on:
HEAD commit: a2cc6ff5ec8f Merge tag 'firewire-updates-6.15' of git://gi..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1007f7b0580000
kernel config: https://syzkaller.appspot.com/x/.config?x=adffebefc9feb9d6
dashboard link: https://syzkaller.appspot.com/bug?extid=6279b273d888c2017726
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12202fb0580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1417e94c580000
Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-a2cc6ff5.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ebd4f463c5cb/vmlinux-a2cc6ff5.xz
kernel image: https://storage.googleapis.com/syzbot-assets/91fd93bd91b3/bzImage-a2cc6ff5.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+6279b273d888c2017726@syzkaller.appspotmail.com
======================================================
WARNING: possible circular locking dependency detected
6.14.0-syzkaller-12966-ga2cc6ff5ec8f #0 Not tainted
------------------------------------------------------
syz-executor876/5939 is trying to acquire lock:
ffff8880261b2318 (&q->elevator_lock){+.+.}-{4:4}, at: blk_mq_elv_switch_none block/blk-mq.c:4942 [inline]
ffff8880261b2318 (&q->elevator_lock){+.+.}-{4:4}, at: __blk_mq_update_nr_hw_queues block/blk-mq.c:5022 [inline]
ffff8880261b2318 (&q->elevator_lock){+.+.}-{4:4}, at: blk_mq_update_nr_hw_queues+0x4a9/0x1360 block/blk-mq.c:5074
but task is already holding lock:
ffff8880261b1de8 (&q->q_usage_counter(io)#49){++++}-{0:0}, at: blk_mq_freeze_queue_nomemsave block/blk-mq.c:215 [inline]
ffff8880261b1de8 (&q->q_usage_counter(io)#49){++++}-{0:0}, at: __blk_mq_update_nr_hw_queues block/blk-mq.c:5014 [inline]
ffff8880261b1de8 (&q->q_usage_counter(io)#49){++++}-{0:0}, at: blk_mq_update_nr_hw_queues+0x263/0x1360 block/blk-mq.c:5074
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (&q->q_usage_counter(io)#49){++++}-{0:0}:
blk_alloc_queue+0x619/0x760 block/blk-core.c:461
blk_mq_alloc_queue+0x179/0x290 block/blk-mq.c:4349
__blk_mq_alloc_disk+0x29/0x120 block/blk-mq.c:4396
nbd_dev_add+0x49d/0xbb0 drivers/block/nbd.c:1933
nbd_init+0x181/0x320 drivers/block/nbd.c:2670
do_one_initcall+0x120/0x6e0 init/main.c:1257
do_initcall_level init/main.c:1319 [inline]
do_initcalls init/main.c:1335 [inline]
do_basic_setup init/main.c:1354 [inline]
kernel_init_freeable+0x5c2/0x900 init/main.c:1567
kernel_init+0x1c/0x2b0 init/main.c:1457
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
-> #1 (fs_reclaim){+.+.}-{0:0}:
__fs_reclaim_acquire mm/page_alloc.c:4028 [inline]
fs_reclaim_acquire+0x102/0x150 mm/page_alloc.c:4042
might_alloc include/linux/sched/mm.h:318 [inline]
xa_insert include/linux/xarray.h:783 [inline]
blk_mq_init_hctx block/blk-mq.c:3924 [inline]
blk_mq_alloc_and_init_hctx+0x503/0x11c0 block/blk-mq.c:4457
blk_mq_realloc_hw_ctxs+0x8f6/0xc00 block/blk-mq.c:4486
blk_mq_init_allocated_queue+0x3af/0x1230 block/blk-mq.c:4540
blk_mq_alloc_queue+0x1c2/0x290 block/blk-mq.c:4353
__blk_mq_alloc_disk+0x29/0x120 block/blk-mq.c:4396
loop_add+0x496/0xb70 drivers/block/loop.c:2067
loop_init+0x164/0x270 drivers/block/loop.c:2302
do_one_initcall+0x120/0x6e0 init/main.c:1257
do_initcall_level init/main.c:1319 [inline]
do_initcalls init/main.c:1335 [inline]
do_basic_setup init/main.c:1354 [inline]
kernel_init_freeable+0x5c2/0x900 init/main.c:1567
kernel_init+0x1c/0x2b0 init/main.c:1457
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
-> #0 (&q->elevator_lock){+.+.}-{4:4}:
check_prev_add kernel/locking/lockdep.c:3166 [inline]
check_prevs_add kernel/locking/lockdep.c:3285 [inline]
validate_chain kernel/locking/lockdep.c:3909 [inline]
__lock_acquire+0x1173/0x1ba0 kernel/locking/lockdep.c:5235
lock_acquire kernel/locking/lockdep.c:5866 [inline]
lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5823
__mutex_lock_common kernel/locking/mutex.c:601 [inline]
__mutex_lock+0x199/0xb90 kernel/locking/mutex.c:746
blk_mq_elv_switch_none block/blk-mq.c:4942 [inline]
__blk_mq_update_nr_hw_queues block/blk-mq.c:5022 [inline]
blk_mq_update_nr_hw_queues+0x4a9/0x1360 block/blk-mq.c:5074
nbd_start_device+0x172/0xcd0 drivers/block/nbd.c:1476
nbd_start_device_ioctl drivers/block/nbd.c:1527 [inline]
__nbd_ioctl drivers/block/nbd.c:1602 [inline]
nbd_ioctl+0x219/0xda0 drivers/block/nbd.c:1642
blkdev_ioctl+0x274/0x6d0 block/ioctl.c:698
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:906 [inline]
__se_sys_ioctl fs/ioctl.c:892 [inline]
__x64_sys_ioctl+0x190/0x200 fs/ioctl.c:892
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
other info that might help us debug this:
Chain exists of:
&q->elevator_lock --> fs_reclaim --> &q->q_usage_counter(io)#49
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&q->q_usage_counter(io)#49);
lock(fs_reclaim);
lock(&q->q_usage_counter(io)#49);
lock(&q->elevator_lock);
*** DEADLOCK ***
4 locks held by syz-executor876/5939:
#0: ffff8880261c3998 (&nbd->config_lock){+.+.}-{4:4}, at: nbd_ioctl+0x150/0xda0 drivers/block/nbd.c:1635
#1: ffff8880261c38d8 (&set->tag_list_lock){+.+.}-{4:4}, at: blk_mq_update_nr_hw_queues+0x8e/0x1360 block/blk-mq.c:5073
#2: ffff8880261b1de8 (&q->q_usage_counter(io)#49){++++}-{0:0}, at: blk_mq_freeze_queue_nomemsave block/blk-mq.c:215 [inline]
#2: ffff8880261b1de8 (&q->q_usage_counter(io)#49){++++}-{0:0}, at: __blk_mq_update_nr_hw_queues block/blk-mq.c:5014 [inline]
#2: ffff8880261b1de8 (&q->q_usage_counter(io)#49){++++}-{0:0}, at: blk_mq_update_nr_hw_queues+0x263/0x1360 block/blk-mq.c:5074
#3: ffff8880261b1e20 (&q->q_usage_counter(queue)){+.+.}-{0:0}, at: blk_mq_freeze_queue_nomemsave block/blk-mq.c:215 [inline]
#3: ffff8880261b1e20 (&q->q_usage_counter(queue)){+.+.}-{0:0}, at: __blk_mq_update_nr_hw_queues block/blk-mq.c:5014 [inline]
#3: ffff8880261b1e20 (&q->q_usage_counter(queue)){+.+.}-{0:0}, at: blk_mq_update_nr_hw_queues+0x263/0x1360 block/blk-mq.c:5074
stack backtrace:
CPU: 3 UID: 0 PID: 5939 Comm: syz-executor876 Not tainted 6.14.0-syzkaller-12966-ga2cc6ff5ec8f #0 PREEMPT(full)
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+0x275/0x350 kernel/locking/lockdep.c:2079
check_noncircular+0x14c/0x170 kernel/locking/lockdep.c:2211
check_prev_add kernel/locking/lockdep.c:3166 [inline]
check_prevs_add kernel/locking/lockdep.c:3285 [inline]
validate_chain kernel/locking/lockdep.c:3909 [inline]
__lock_acquire+0x1173/0x1ba0 kernel/locking/lockdep.c:5235
lock_acquire kernel/locking/lockdep.c:5866 [inline]
lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5823
__mutex_lock_common kernel/locking/mutex.c:601 [inline]
__mutex_lock+0x199/0xb90 kernel/locking/mutex.c:746
blk_mq_elv_switch_none block/blk-mq.c:4942 [inline]
__blk_mq_update_nr_hw_queues block/blk-mq.c:5022 [inline]
blk_mq_update_nr_hw_queues+0x4a9/0x1360 block/blk-mq.c:5074
nbd_start_device+0x172/0xcd0 drivers/block/nbd.c:1476
nbd_start_device_ioctl drivers/block/nbd.c:1527 [inline]
__nbd_ioctl drivers/block/nbd.c:1602 [inline]
nbd_ioctl+0x219/0xda0 drivers/block/nbd.c:1642
blkdev_ioctl+0x274/0x6d0 block/ioctl.c:698
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:906 [inline]
__se_sys_ioctl fs/ioctl.c:892 [inline]
__x64_sys_ioctl+0x190/0x200 fs/ioctl.c:892
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe4217ab4a9
Code: 48 83 c4 28 c3 e8 37 17 00 00 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe73ad6c28 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007ffe73ad6df8 RCX: 00007fe4217ab4a9
RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000003
RBP: 00007fe42181e610 R08: 00007ffe73ad6df8 R09: 00007ffe73ad6df8
R10: 00007ffe73ad6df8 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffe73ad6de8 R14: 0000000000000001 R15: 0000000000000001
</TASK>
---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [syzbot] [block?] possible deadlock in blk_mq_update_nr_hw_queues
2024-11-24 23:13 [syzbot] [block?] possible deadlock in blk_mq_update_nr_hw_queues syzbot
2025-04-03 19:36 ` syzbot
@ 2025-07-13 12:20 ` syzbot
1 sibling, 0 replies; 3+ messages in thread
From: syzbot @ 2025-07-13 12:20 UTC (permalink / raw)
To: axboe, hch, linux-block, linux-kernel, ming.lei, netdev,
syzkaller-bugs
syzbot has bisected this issue to:
commit f1be1788a32e8fa63416ad4518bbd1a85a825c9d
Author: Ming Lei <ming.lei@redhat.com>
Date: Fri Oct 25 00:37:20 2024 +0000
block: model freeze & enter queue as lock for supporting lockdep
bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=14ea5d82580000
start commit: a52f9f0d77f2 Merge tag 'batadv-next-pullrequest-20250710' ..
git tree: net-next
final oops: https://syzkaller.appspot.com/x/report.txt?x=16ea5d82580000
console output: https://syzkaller.appspot.com/x/log.txt?x=12ea5d82580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f8235fb7e74dd7f6
dashboard link: https://syzkaller.appspot.com/bug?extid=6279b273d888c2017726
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14321d82580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=179590f0580000
Reported-by: syzbot+6279b273d888c2017726@syzkaller.appspotmail.com
Fixes: f1be1788a32e ("block: model freeze & enter queue as lock for supporting lockdep")
For information about bisection process see: https://goo.gl/tpsmEJ#bisection
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2025-07-13 12:20 UTC | newest]
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