======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.3.859/9118 is trying to acquire lock:
ffffffff8e245220 (fs_reclaim){+.+.}-{0:0}, at: might_alloc include/linux/sched/mm.h:318 [inline]
ffffffff8e245220 (fs_reclaim){+.+.}-{0:0}, at: slab_pre_alloc_hook mm/slub.c:4898 [inline]
ffffffff8e245220 (fs_reclaim){+.+.}-{0:0}, at: slab_alloc_node mm/slub.c:5222 [inline]
ffffffff8e245220 (fs_reclaim){+.+.}-{0:0}, at: __do_kmalloc_node mm/slub.c:5603 [inline]
ffffffff8e245220 (fs_reclaim){+.+.}-{0:0}, at: __kmalloc_noprof+0x9c/0x7f0 mm/slub.c:5616
but task is already holding lock:
ffffffff8dfe3a48 (wq_pool_mutex){+.+.}-{4:4}, at: apply_wqattrs_lock kernel/workqueue.c:5211 [inline]
ffffffff8dfe3a48 (wq_pool_mutex){+.+.}-{4:4}, at: __alloc_workqueue+0x9f0/0x1b80 kernel/workqueue.c:5766
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #8 (wq_pool_mutex){+.+.}-{4:4}:
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
__mutex_lock_common kernel/locking/mutex.c:598 [inline]
__mutex_lock+0x187/0x1350 kernel/locking/mutex.c:760
apply_wqattrs_lock kernel/workqueue.c:5211 [inline]
__alloc_workqueue+0x9f0/0x1b80 kernel/workqueue.c:5766
alloc_workqueue_noprof+0xd4/0x210 kernel/workqueue.c:5818
padata_alloc+0xc1/0x370 kernel/padata.c:970
pcrypt_init_padata+0x27/0x100 crypto/pcrypt.c:328
pcrypt_init+0x60/0xc0 crypto/pcrypt.c:353
do_one_initcall+0x236/0x820 init/main.c:1283
do_initcall_level+0x104/0x190 init/main.c:1345
do_initcalls+0x59/0xa0 init/main.c:1361
kernel_init_freeable+0x334/0x4b0 init/main.c:1593
kernel_init+0x1d/0x1d0 init/main.c:1483
ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
-> #7 (cpu_hotplug_lock){++++}-{0:0}:
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
percpu_down_read_internal include/linux/percpu-rwsem.h:53 [inline]
percpu_down_read include/linux/percpu-rwsem.h:77 [inline]
cpus_read_lock+0x42/0x160 kernel/cpu.c:491
static_key_slow_inc+0x12/0x30 kernel/jump_label.c:190
tcp_md5_do_add+0x21f/0x3a0 net/ipv4/tcp_ipv4.c:1436
tcp_v4_parse_md5_keys+0x412/0x600 net/ipv4/tcp_ipv4.c:1577
do_tcp_setsockopt+0x11dc/0x1f20 net/ipv4/tcp.c:4059
do_sock_setsockopt+0x17c/0x1b0 net/socket.c:2360
__sys_setsockopt net/socket.c:2385 [inline]
__do_sys_setsockopt net/socket.c:2391 [inline]
__se_sys_setsockopt net/socket.c:2388 [inline]
__x64_sys_setsockopt+0x13f/0x1b0 net/socket.c:2388
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #6 (sk_lock-AF_INET){+.+.}-{0:0}:
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
lock_sock_nested+0x48/0x100 net/core/sock.c:3720
lock_sock include/net/sock.h:1679 [inline]
inet_shutdown+0x6a/0x390 net/ipv4/af_inet.c:907
nbd_mark_nsock_dead+0x2e9/0x560 drivers/block/nbd.c:318
sock_shutdown+0x15e/0x260 drivers/block/nbd.c:411
nbd_clear_sock drivers/block/nbd.c:1424 [inline]
nbd_config_put+0x342/0x790 drivers/block/nbd.c:1448
nbd_release+0xfe/0x140 drivers/block/nbd.c:1753
bdev_release+0x536/0x650 block/bdev.c:-1
blkdev_release+0x15/0x20 block/fops.c:702
__fput+0x44c/0xa70 fs/file_table.c:468
task_work_run+0x1d4/0x260 kernel/task_work.c:227
exit_task_work include/linux/task_work.h:40 [inline]
do_exit+0x6b5/0x2300 kernel/exit.c:966
do_group_exit+0x21c/0x2d0 kernel/exit.c:1107
get_signal+0x1285/0x1340 kernel/signal.c:3034
arch_do_signal_or_restart+0xa0/0x790 arch/x86/kernel/signal.c:337
exit_to_user_mode_loop+0x72/0x130 kernel/entry/common.c:40
exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
do_syscall_64+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #5 (&nsock->tx_lock){+.+.}-{4:4}:
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
__mutex_lock_common kernel/locking/mutex.c:598 [inline]
__mutex_lock+0x187/0x1350 kernel/locking/mutex.c:760
nbd_handle_cmd drivers/block/nbd.c:1140 [inline]
nbd_queue_rq+0x257/0xf10 drivers/block/nbd.c:1204
blk_mq_dispatch_rq_list+0x4c0/0x1900 block/blk-mq.c:2129
__blk_mq_do_dispatch_sched block/blk-mq-sched.c:168 [inline]
blk_mq_do_dispatch_sched block/blk-mq-sched.c:182 [inline]
__blk_mq_sched_dispatch_requests+0xda4/0x1570 block/blk-mq-sched.c:307
blk_mq_sched_dispatch_requests+0xd7/0x190 block/blk-mq-sched.c:329
blk_mq_run_hw_queue+0x348/0x4f0 block/blk-mq.c:2367
blk_mq_dispatch_list+0xd0c/0xe00 include/linux/spinlock.h:-1
blk_mq_flush_plug_list+0x469/0x550 block/blk-mq.c:2976
__blk_flush_plug+0x3d3/0x4b0 block/blk-core.c:1225
blk_finish_plug block/blk-core.c:1252 [inline]
__submit_bio+0x2d3/0x5a0 block/blk-core.c:651
__submit_bio_noacct_mq block/blk-core.c:724 [inline]
submit_bio_noacct_nocheck+0x2fb/0xa50 block/blk-core.c:755
submit_bh fs/buffer.c:2829 [inline]
block_read_full_folio+0x599/0x830 fs/buffer.c:2447
filemap_read_folio+0x117/0x380 mm/filemap.c:2444
do_read_cache_folio+0x350/0x590 mm/filemap.c:4024
read_mapping_folio include/linux/pagemap.h:999 [inline]
read_part_sector+0xb6/0x2b0 block/partitions/core.c:722
adfspart_check_ICS+0xa4/0xa50 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+0x75f/0x14b0 block/partitions/core.c:693
blkdev_get_whole+0x380/0x510 block/bdev.c:748
bdev_open+0x31e/0xd30 block/bdev.c:957
blkdev_open+0x457/0x600 block/fops.c:694
do_dentry_open+0x953/0x13f0 fs/open.c:965
vfs_open+0x3b/0x340 fs/open.c:1097
do_open fs/namei.c:3975 [inline]
path_openat+0x2ee5/0x3830 fs/namei.c:4134
do_filp_open+0x1fa/0x410 fs/namei.c:4161
do_sys_openat2+0x121/0x1c0 fs/open.c:1437
do_sys_open fs/open.c:1452 [inline]
__do_sys_openat fs/open.c:1468 [inline]
__se_sys_openat fs/open.c:1463 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1463
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #4 (&cmd->lock){+.+.}-{4:4}:
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
__mutex_lock_common kernel/locking/mutex.c:598 [inline]
__mutex_lock+0x187/0x1350 kernel/locking/mutex.c:760
nbd_queue_rq+0xc8/0xf10 drivers/block/nbd.c:1196
blk_mq_dispatch_rq_list+0x4c0/0x1900 block/blk-mq.c:2129
__blk_mq_do_dispatch_sched block/blk-mq-sched.c:168 [inline]
blk_mq_do_dispatch_sched block/blk-mq-sched.c:182 [inline]
__blk_mq_sched_dispatch_requests+0xda4/0x1570 block/blk-mq-sched.c:307
blk_mq_sched_dispatch_requests+0xd7/0x190 block/blk-mq-sched.c:329
blk_mq_run_hw_queue+0x348/0x4f0 block/blk-mq.c:2367
blk_mq_dispatch_list+0xd0c/0xe00 include/linux/spinlock.h:-1
blk_mq_flush_plug_list+0x469/0x550 block/blk-mq.c:2976
__blk_flush_plug+0x3d3/0x4b0 block/blk-core.c:1225
blk_finish_plug block/blk-core.c:1252 [inline]
__submit_bio+0x2d3/0x5a0 block/blk-core.c:651
__submit_bio_noacct_mq block/blk-core.c:724 [inline]
submit_bio_noacct_nocheck+0x2fb/0xa50 block/blk-core.c:755
submit_bh fs/buffer.c:2829 [inline]
block_read_full_folio+0x599/0x830 fs/buffer.c:2447
filemap_read_folio+0x117/0x380 mm/filemap.c:2444
do_read_cache_folio+0x350/0x590 mm/filemap.c:4024
read_mapping_folio include/linux/pagemap.h:999 [inline]
read_part_sector+0xb6/0x2b0 block/partitions/core.c:722
adfspart_check_ICS+0xa4/0xa50 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+0x75f/0x14b0 block/partitions/core.c:693
blkdev_get_whole+0x380/0x510 block/bdev.c:748
bdev_open+0x31e/0xd30 block/bdev.c:957
blkdev_open+0x457/0x600 block/fops.c:694
do_dentry_open+0x953/0x13f0 fs/open.c:965
vfs_open+0x3b/0x340 fs/open.c:1097
do_open fs/namei.c:3975 [inline]
path_openat+0x2ee5/0x3830 fs/namei.c:4134
do_filp_open+0x1fa/0x410 fs/namei.c:4161
do_sys_openat2+0x121/0x1c0 fs/open.c:1437
do_sys_open fs/open.c:1452 [inline]
__do_sys_openat fs/open.c:1468 [inline]
__se_sys_openat fs/open.c:1463 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1463
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #3 (set->srcu){.+.+}-{0:0}:
lock_sync+0xba/0x160 kernel/locking/lockdep.c:5916
srcu_lock_sync include/linux/srcu.h:173 [inline]
__synchronize_srcu+0x96/0x3a0 kernel/rcu/srcutree.c:1439
elevator_switch+0x12b/0x640 block/elevator.c:588
elevator_change+0x315/0x4c0 block/elevator.c:691
elevator_set_default+0x186/0x260 block/elevator.c:767
blk_register_queue+0x34e/0x3f0 block/blk-sysfs.c:942
__add_disk+0x677/0xd50 block/genhd.c:528
add_disk_fwnode+0xfc/0x480 block/genhd.c:597
add_disk include/linux/blkdev.h:775 [inline]
nbd_dev_add+0x717/0xae0 drivers/block/nbd.c:1981
nbd_init+0x168/0x1f0 drivers/block/nbd.c:2688
do_one_initcall+0x236/0x820 init/main.c:1283
do_initcall_level+0x104/0x190 init/main.c:1345
do_initcalls+0x59/0xa0 init/main.c:1361
kernel_init_freeable+0x334/0x4b0 init/main.c:1593
kernel_init+0x1d/0x1d0 init/main.c:1483
ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
-> #2 (&q->elevator_lock){+.+.}-{4:4}:
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
__mutex_lock_common kernel/locking/mutex.c:598 [inline]
__mutex_lock+0x187/0x1350 kernel/locking/mutex.c:760
elevator_change+0x1e5/0x4c0 block/elevator.c:689
elevator_set_none+0x42/0xb0 block/elevator.c:782
blk_mq_elv_switch_none block/blk-mq.c:5032 [inline]
__blk_mq_update_nr_hw_queues block/blk-mq.c:5075 [inline]
blk_mq_update_nr_hw_queues+0x598/0x1ab0 block/blk-mq.c:5133
nbd_start_device+0x17f/0xb10 drivers/block/nbd.c:1486
nbd_genl_connect+0x135b/0x18f0 drivers/block/nbd.c:2236
genl_family_rcv_msg_doit+0x215/0x300 net/netlink/genetlink.c:1115
genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]
genl_rcv_msg+0x60e/0x790 net/netlink/genetlink.c:1210
netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2552
genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219
netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1346
netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896
sock_sendmsg_nosec net/socket.c:727 [inline]
__sock_sendmsg+0x21c/0x270 net/socket.c:742
____sys_sendmsg+0x505/0x830 net/socket.c:2630
___sys_sendmsg+0x21f/0x2a0 net/socket.c:2684
__sys_sendmsg net/socket.c:2716 [inline]
__do_sys_sendmsg net/socket.c:2721 [inline]
__se_sys_sendmsg net/socket.c:2719 [inline]
__x64_sys_sendmsg+0x19b/0x260 net/socket.c:2719
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #1 (&q->q_usage_counter(io)#49){++++}-{0:0}:
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
blk_alloc_queue+0x538/0x620 block/blk-core.c:461
blk_mq_alloc_queue block/blk-mq.c:4399 [inline]
__blk_mq_alloc_disk+0x15c/0x340 block/blk-mq.c:4446
nbd_dev_add+0x46c/0xae0 drivers/block/nbd.c:1951
nbd_init+0x168/0x1f0 drivers/block/nbd.c:2688
do_one_initcall+0x236/0x820 init/main.c:1283
do_initcall_level+0x104/0x190 init/main.c:1345
do_initcalls+0x59/0xa0 init/main.c:1361
kernel_init_freeable+0x334/0x4b0 init/main.c:1593
kernel_init+0x1d/0x1d0 init/main.c:1483
ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
-> #0 (fs_reclaim){+.+.}-{0:0}:
check_prev_add kernel/locking/lockdep.c:3165 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3908
__lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
__fs_reclaim_acquire mm/page_alloc.c:4269 [inline]
fs_reclaim_acquire+0x72/0x100 mm/page_alloc.c:4283
might_alloc include/linux/sched/mm.h:318 [inline]
slab_pre_alloc_hook mm/slub.c:4898 [inline]
slab_alloc_node mm/slub.c:5222 [inline]
__do_kmalloc_node mm/slub.c:5603 [inline]
__kmalloc_noprof+0x9c/0x7f0 mm/slub.c:5616
kmalloc_noprof include/linux/slab.h:961 [inline]
kzalloc_noprof include/linux/slab.h:1094 [inline]
apply_wqattrs_prepare+0xf6/0xe00 kernel/workqueue.c:5306
apply_workqueue_attrs_locked+0x65/0x240 kernel/workqueue.c:5396
alloc_and_link_pwqs kernel/workqueue.c:5546 [inline]
__alloc_workqueue+0x10ca/0x1b80 kernel/workqueue.c:5768
alloc_workqueue_noprof+0xd4/0x210 kernel/workqueue.c:5818
hci_register_dev+0x208/0x890 net/bluetooth/hci_core.c:2604
hci_uart_register_dev drivers/bluetooth/hci_ldisc.c:691 [inline]
hci_uart_set_proto drivers/bluetooth/hci_ldisc.c:717 [inline]
hci_uart_tty_ioctl+0x828/0xa00 drivers/bluetooth/hci_ldisc.c:771
tty_ioctl+0x9c6/0xde0 drivers/tty/tty_io.c:2801
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 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:
fs_reclaim --> cpu_hotplug_lock --> wq_pool_mutex
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(wq_pool_mutex);
lock(cpu_hotplug_lock);
lock(wq_pool_mutex);
lock(fs_reclaim);
*** DEADLOCK ***
2 locks held by syz.3.859/9118:
#0: ffff88807bb910a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffffff8dfe3a48 (wq_pool_mutex){+.+.}-{4:4}, at: apply_wqattrs_lock kernel/workqueue.c:5211 [inline]
#1: ffffffff8dfe3a48 (wq_pool_mutex){+.+.}-{4:4}, at: __alloc_workqueue+0x9f0/0x1b80 kernel/workqueue.c:5766
stack backtrace:
CPU: 0 UID: 0 PID: 9118 Comm: syz.3.859 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
<TASK>
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
print_circular_bug+0x2ee/0x310 kernel/locking/lockdep.c:2043
check_noncircular+0x134/0x160 kernel/locking/lockdep.c:2175
check_prev_add kernel/locking/lockdep.c:3165 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3908
__lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
__fs_reclaim_acquire mm/page_alloc.c:4269 [inline]
fs_reclaim_acquire+0x72/0x100 mm/page_alloc.c:4283
might_alloc include/linux/sched/mm.h:318 [inline]
slab_pre_alloc_hook mm/slub.c:4898 [inline]
slab_alloc_node mm/slub.c:5222 [inline]
__do_kmalloc_node mm/slub.c:5603 [inline]
__kmalloc_noprof+0x9c/0x7f0 mm/slub.c:5616
kmalloc_noprof include/linux/slab.h:961 [inline]
kzalloc_noprof include/linux/slab.h:1094 [inline]
apply_wqattrs_prepare+0xf6/0xe00 kernel/workqueue.c:5306
apply_workqueue_attrs_locked+0x65/0x240 kernel/workqueue.c:5396
alloc_and_link_pwqs kernel/workqueue.c:5546 [inline]
__alloc_workqueue+0x10ca/0x1b80 kernel/workqueue.c:5768
alloc_workqueue_noprof+0xd4/0x210 kernel/workqueue.c:5818
hci_register_dev+0x208/0x890 net/bluetooth/hci_core.c:2604
hci_uart_register_dev drivers/bluetooth/hci_ldisc.c:691 [inline]
hci_uart_set_proto drivers/bluetooth/hci_ldisc.c:717 [inline]
hci_uart_tty_ioctl+0x828/0xa00 drivers/bluetooth/hci_ldisc.c:771
tty_ioctl+0x9c6/0xde0 drivers/tty/tty_io.c:2801
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f6c5e38eec9
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:00007f6c5f1fa038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f6c5e5e5fa0 RCX: 00007f6c5e38eec9
RDX: 0000000000000000 RSI: 00000000400455c8 RDI: 0000000000000003
RBP: 00007f6c5e411f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6c5e5e6038 R14: 00007f6c5e5e5fa0 R15: 00007ffee1a1ffb8
</TASK>