[v5.15] INFO: task hung in blkdev_get_by_dev (5)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: cc5ec8769306 Linux 5.15.196
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=10453114580000
kernel config: https://syzkaller.appspot.com/x/.config?x=e1bb6d24ef2164eb
dashboard link: https://syzkaller.appspot.com/bug?extid=0d446208a1f1e6c0e1fe
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/c71c660545b2/disk-cc5ec876.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/4f011826cca6/vmlinux-cc5ec876.xz
kernel image: https://storage.googleapis.com/syzbot-assets/8ccd1a2c3f8c/bzImage-cc5ec876.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+0d4462...@syzkaller.appspotmail.com

INFO: task udevd:3562 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd state:D stack:25376 pid: 3562 ppid: 1 flags:0x00004002
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11bb/0x4390 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
__mutex_lock_common+0xc71/0x2390 kernel/locking/mutex.c:669
__mutex_lock kernel/locking/mutex.c:729 [inline]
mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
blkdev_get_by_dev+0x157/0xa60 block/bdev.c:820
blkdev_open+0x12d/0x2c0 block/fops.c:466
do_dentry_open+0x7ff/0xf80 fs/open.c:826
do_open fs/namei.c:3616 [inline]
path_openat+0x2682/0x2f30 fs/namei.c:3750
do_filp_open+0x1b3/0x3e0 fs/namei.c:3777
do_sys_openat2+0x142/0x4a0 fs/open.c:1253
do_sys_open fs/open.c:1269 [inline]
__do_sys_openat fs/open.c:1285 [inline]
__se_sys_openat fs/open.c:1280 [inline]
__x64_sys_openat+0x135/0x160 fs/open.c:1280
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fb70d285407
RSP: 002b:00007ffda5046720 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fb70d197880 RCX: 00007fb70d285407
RDX: 00000000000a0800 RSI: 00005583d69126d0 RDI: ffffffffffffff9c
RBP: 00005583d68efee0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 00005583ad21b100 R14: 0000000000000000 R15: 00007ffda50469b0
</TASK>
INFO: task udevd:4583 blocked for more than 144 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd state:D stack:23264 pid: 4583 ppid: 3562 flags:0x00004002
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11bb/0x4390 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
io_schedule+0x7c/0xd0 kernel/sched/core.c:8503
wait_on_page_bit_common+0x815/0xe00 mm/filemap.c:1356
wait_on_page_bit mm/filemap.c:1417 [inline]
wait_on_page_locked include/linux/pagemap.h:688 [inline]
wait_on_page_read mm/filemap.c:3437 [inline]
do_read_cache_page+0xb05/0x1030 mm/filemap.c:3480
read_mapping_page include/linux/pagemap.h:515 [inline]
read_part_sector+0xd4/0x4f0 block/partitions/core.c:731
adfspart_check_ICS+0xbf/0xe00 block/partitions/acorn.c:360
check_partition block/partitions/core.c:148 [inline]
blk_add_partitions block/partitions/core.c:616 [inline]
bdev_disk_changed+0x917/0x16b0 block/partitions/core.c:702
blkdev_get_whole+0x2f9/0x390 block/bdev.c:682
blkdev_get_by_dev+0x2d0/0xa60 block/bdev.c:827
blkdev_open+0x12d/0x2c0 block/fops.c:466
do_dentry_open+0x7ff/0xf80 fs/open.c:826
do_open fs/namei.c:3616 [inline]
path_openat+0x2682/0x2f30 fs/namei.c:3750
do_filp_open+0x1b3/0x3e0 fs/namei.c:3777
do_sys_openat2+0x142/0x4a0 fs/open.c:1253
do_sys_open fs/open.c:1269 [inline]
__do_sys_openat fs/open.c:1285 [inline]
__se_sys_openat fs/open.c:1280 [inline]
__x64_sys_openat+0x135/0x160 fs/open.c:1280
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fb70d285407
RSP: 002b:00007ffda5046560 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fb70d197880 RCX: 00007fb70d285407
RDX: 00000000000a0800 RSI: 00005583d68fae20 RDI: ffffffffffffff9c
RBP: 00005583d68e8910 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00005583d691f340
R13: 00005583d6900410 R14: 0000000000000000 R15: 00005583d691f340
</TASK>
INFO: task syz.1.65:4697 blocked for more than 145 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.65 state:D
stack:27664 pid: 4697 ppid: 4183 flags:0x00004004
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11bb/0x4390 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
__mutex_lock_common+0xc71/0x2390 kernel/locking/mutex.c:669
__mutex_lock kernel/locking/mutex.c:729 [inline]
mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
blkdev_put+0xf9/0x7d0 block/bdev.c:915
blkdev_close+0x76/0xa0 block/fops.c:478
__fput+0x234/0x930 fs/file_table.c:311
task_work_run+0x125/0x1a0 kernel/task_work.c:188
tracehook_notify_resume include/linux/tracehook.h:189 [inline]
exit_to_user_mode_loop+0x10f/0x130 kernel/entry/common.c:181
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
__syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f4bc19a46c9
RSP: 002b:00007f4bbfc0b038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: 0000000000000000 RBX: 00007f4bc1bfafa0 RCX: 00007f4bc19a46c9
RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000003
RBP: 00007f4bc1a26f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4bc1bfb038 R14: 00007f4bc1bfafa0 R15: 00007ffc6d698c08
</TASK>

Showing all locks held in the system:
3 locks held by kworker/u4:0/9:
1 lock held by khungtaskd/27:
#0: ffffffff8c11c760 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
1 lock held by udevd/3562:
#0: ffff88801f8a8518 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x157/0xa60 block/bdev.c:820
2 locks held by getty/3954:
#0: ffff88814d6ba098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
#1: ffffc900026562e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x5ba/0x1a30 drivers/tty/n_tty.c:2158
2 locks held by kworker/0:5/4238:
#0: ffff888016872138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
#1: ffffc900031dfd00 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
3 locks held by kworker/1:8/4316:
#0: ffff888016870938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
#1: ffffc90003da7d00 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
#2: ffff888075781240 (&data->fib_lock){+.+.}-{3:3}, at: nsim_fib_event_work+0x271/0x3240 drivers/net/netdevsim/fib.c:1480
2 locks held by kworker/1:17/4418:
#0: ffff888016870938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
#1: ffffc9000341fd00 ((work_completion)(&pwq->unbound_release_work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
1 lock held by udevd/4583:
#0: ffff88801f8a8518 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x157/0xa60 block/bdev.c:820
1 lock held by syz.1.65/4697:
#0: ffff88801f8a8518 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xf9/0x7d0 block/bdev.c:915
2 locks held by dhcpcd/5009:
#0: ffff888073302610 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
#0: ffff888073302610 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: __sock_release net/socket.c:650 [inline]
#0: ffff888073302610 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: sock_close+0x90/0x240 net/socket.c:1346
#1: ffffffff8c1211e8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:322 [inline]
#1: ffffffff8c1211e8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x320/0x6b0 kernel/rcu/tree_exp.h:845
2 locks held by kworker/0:8/5085:
#0: ffff888016870938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
#1: ffffc9000365fd00 ((work_completion)(&fw_work->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
3 locks held by kworker/0:20/5833:
#0: ffff888016870938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
#1: ffffc9000386fd00 ((work_completion)(&pwq->unbound_release_work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
#2: ffffffff8c1211e8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:290 [inline]
#2: ffffffff8c1211e8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x347/0x6b0 kernel/rcu/tree_exp.h:845
2 locks held by kworker/u4:15/6390:

=============================================

NMI backtrace for cpu 1
CPU: 1 PID: 27 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
<TASK>
dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
nmi_cpu_backtrace+0x397/0x3d0 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline]
watchdog+0xe0f/0xe50 kernel/hung_task.c:369
kthread+0x436/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
</TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 6390 Comm: kworker/u4:15 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Workqueue: phy14 ieee80211_iface_work
RIP: 0010:should_resched arch/x86/include/asm/preempt.h:-1 [inline]
RIP: 0010:unwind_next_frame+0x129d/0x1d90 arch/x86/kernel/unwind_orc.c:616
Code: 0f 85 a0 02 00 00 c6 05 12 6c 21 0c 01 48 c7 c7 00 85 08 8a e9 3d fa ff ff bf 01 00 00 00 e8 fa e6 1c 00 65 8b 0d 8b e4 cd 7e <b0> 01 85 c9 0f 85 d3 02 00 00 e8 34 ef cb ff e9 c9 02 00 00 80 3d
RSP: 0018:ffffc9000325f468 EFLAGS: 00000297
RAX: 0000000080000001 RBX: ffffc9000325f528 RCX: 0000000080000000
RDX: ffffc9000325f501 RSI: ffffc9000325fdb8 RDI: 00000000ffffffff
RBP: ffffc9000325f570 R08: dffffc0000000000 R09: ffffc9000325f578
R10: fffff5200064beb1 R11: 1ffff9200064beaf R12: ffffc90003258000
R13: dffffc0000000000 R14: ffffc9000325f538 R15: ffffc9000325fdc8
FS: 0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3a1f473e9c CR3: 000000004f646000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
arch_stack_walk+0x10c/0x140 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x98/0xe0 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track+0x4b/0x70 mm/kasan/common.c:46
kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360
____kasan_slab_free+0xd5/0x110 mm/kasan/common.c:366
kasan_slab_free include/linux/kasan.h:230 [inline]
slab_free_hook mm/slub.c:1710 [inline]
slab_free_freelist_hook+0xea/0x170 mm/slub.c:1736
slab_free mm/slub.c:3504 [inline]
kfree+0xef/0x2a0 mm/slub.c:4564
ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1615 [inline]
ieee80211_ibss_rx_queued_mgmt+0x1888/0x29c0 net/mac80211/ibss.c:1643
ieee80211_iface_process_skb net/mac80211/iface.c:1459 [inline]
ieee80211_iface_work+0x70e/0xc60 net/mac80211/iface.c:1513
process_one_work+0x863/0x1000 kernel/workqueue.c:2310
worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
kthread+0x436/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
</TASK>


---
This report is generated by a bot. It may contain errors.
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If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want to overwrite report's subsystems, reply with:
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(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: cc5ec8769306 Linux 5.15.196
git tree: linux-5.15.y

console output: https://syzkaller.appspot.com/x/log.txt?x=17abb084580000

kernel config: https://syzkaller.appspot.com/x/.config?x=e1bb6d24ef2164eb
dashboard link: https://syzkaller.appspot.com/bug?extid=0d446208a1f1e6c0e1fe
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1380a60a580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14721a92580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/c71c660545b2/disk-cc5ec876.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/4f011826cca6/vmlinux-cc5ec876.xz
kernel image: https://storage.googleapis.com/syzbot-assets/8ccd1a2c3f8c/bzImage-cc5ec876.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+0d4462...@syzkaller.appspotmail.com

INFO: task udevd:3560 blocked for more than 143 seconds.

Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.

task:udevd state:D stack:24800 pid: 3560 ppid: 1 flags:0x00004002

Call Trace:
<TASK>
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11bb/0x4390 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
__mutex_lock_common+0xc71/0x2390 kernel/locking/mutex.c:669
__mutex_lock kernel/locking/mutex.c:729 [inline]
mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
blkdev_get_by_dev+0x157/0xa60 block/bdev.c:820
blkdev_open+0x12d/0x2c0 block/fops.c:466
do_dentry_open+0x7ff/0xf80 fs/open.c:826
do_open fs/namei.c:3616 [inline]
path_openat+0x2682/0x2f30 fs/namei.c:3750
do_filp_open+0x1b3/0x3e0 fs/namei.c:3777
do_sys_openat2+0x142/0x4a0 fs/open.c:1253
do_sys_open fs/open.c:1269 [inline]
__do_sys_openat fs/open.c:1285 [inline]
__se_sys_openat fs/open.c:1280 [inline]
__x64_sys_openat+0x135/0x160 fs/open.c:1280
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0

RIP: 0033:0x7f6eec246407
RSP: 002b:00007ffdabb3c3b0 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f6eec158880 RCX: 00007f6eec246407
RDX: 00000000000a0800 RSI: 00005620f6bbc6e0 RDI: ffffffffffffff9c
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000

R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000

R13: 00005620ced91100 R14: 0000000000000000 R15: 00007ffdabb3c640
</TASK>
INFO: task udevd:4285 blocked for more than 143 seconds.

Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.

task:udevd state:D stack:24800 pid: 4285 ppid: 3560 flags:0x00004002

RIP: 0033:0x7f6eec246407
RSP: 002b:00007ffdabb3c1f0 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f6eec158880 RCX: 00007f6eec246407
RDX: 00000000000a0800 RSI: 00005620f6bce240 RDI: ffffffffffffff9c
RBP: 00005620f6ba6910 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00005620f6bce070
R13: 00005620f6bbe410 R14: 0000000000000000 R15: 00005620f6bce070
</TASK>
INFO: task syz.0.30:4586 blocked for more than 144 seconds.

Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.

task:syz.0.30 state:D stack:27200 pid: 4586 ppid: 4372 flags:0x00004004

Call Trace:
<TASK>
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11bb/0x4390 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
__mutex_lock_common+0xc71/0x2390 kernel/locking/mutex.c:669
__mutex_lock kernel/locking/mutex.c:729 [inline]
mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
blkdev_put+0xf9/0x7d0 block/bdev.c:915
blkdev_close+0x76/0xa0 block/fops.c:478
__fput+0x234/0x930 fs/file_table.c:311
task_work_run+0x125/0x1a0 kernel/task_work.c:188
tracehook_notify_resume include/linux/tracehook.h:189 [inline]
exit_to_user_mode_loop+0x10f/0x130 kernel/entry/common.c:181
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
__syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x66/0xd0

RIP: 0033:0x7fead19be6c9
RSP: 002b:00007fead102d038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: 0000000000000000 RBX: 00007fead1c14fa0 RCX: 00007fead19be6c9

RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000003

RBP: 00007fead1a40f91 R08: 0000000000000000 R09: 0000000000000000

R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000

R13: 00007fead1c15038 R14: 00007fead1c14fa0 R15: 00007ffdd9b3dd48

</TASK>

Showing all locks held in the system:

1 lock held by khungtaskd/27:
#0: ffffffff8c11c760 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30

2 locks held by kworker/u5:0/146:
#0: ffff8880207e9938 ((wq_completion)nbd1-recv){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
#1: ffffc9000172fd00 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
1 lock held by udevd/3560:
#0: ffff888020728518 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x157/0xa60 block/bdev.c:820
2 locks held by getty/3945:
#0: ffff88814cccd098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252

#1: ffffc900026562e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x5ba/0x1a30 drivers/tty/n_tty.c:2158

1 lock held by udevd/4285:
#0: ffff888020728518 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x157/0xa60 block/bdev.c:820
1 lock held by syz.0.30/4586:
#0: ffff888020728518 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xf9/0x7d0 block/bdev.c:915
1 lock held by syz.1.198/4983:
#0: ffff88802058da08 (&nbd->config_lock){+.+.}-{3:3}, at: nbd_ioctl+0x140/0xe40 drivers/block/nbd.c:1460

=============================================

NMI backtrace for cpu 0
CPU: 0 PID: 27 Comm: khungtaskd Not tainted syzkaller #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
<TASK>
dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
nmi_cpu_backtrace+0x397/0x3d0 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline]
watchdog+0xe0f/0xe50 kernel/hung_task.c:369
kthread+0x436/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
</TASK>

Sending NMI from CPU 0 to CPUs 1:

NMI backtrace for cpu 1

CPU: 1 PID: 761 Comm: kworker/u4:3 Not tainted syzkaller #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025

Workqueue: phy6 ieee80211_iface_work
RIP: 0010:check_wait_context kernel/locking/lockdep.c:-1 [inline]
RIP: 0010:__lock_acquire+0x876/0x7c60 kernel/locking/lockdep.c:4962
Code: 98 00 00 00 75 24 48 8b 84 24 c0 00 00 00 42 0f b6 04 00 84 c0 0f 85 3c 64 00 00 41 83 3f 00 41 0f 94 c5 45 00 ed 41 80 c5 02 <48> 8b 84 24 88 00 00 00 42 0f b6 04 00 84 c0 0f 85 99 61 00 00 44
RSP: 0018:ffffc90003fcf7c0 EFLAGS: 00000002
RAX: 0000000000000000 RBX: ffff88801f6ae428 RCX: 0000000000000002
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8ffbe0c0
RBP: ffffc90003fcfa10 R08: dffffc0000000000 R09: fffffbfff1ff7c19
R10: fffffbfff1ff7c19 R11: 1ffffffff1ff7c18 R12: 0000000000000000
R13: ffff88801f6ae404 R14: 0000000000000000 R15: ffff88801f6ae414
FS: 0000000000000000(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 00007fb2298d9f98 CR3: 0000000074b68000 CR4: 00000000003506e0

DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>

lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623
_raw_spin_lock_nested+0x2e/0x40 kernel/locking/spinlock.c:368
raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:475
raw_spin_rq_lock kernel/sched/sched.h:1326 [inline]
rq_lock kernel/sched/sched.h:1621 [inline]
ttwu_queue kernel/sched/core.c:3840 [inline]
try_to_wake_up+0x533/0x1050 kernel/sched/core.c:4165
wake_up_worker kernel/workqueue.c:859 [inline]
process_one_work+0x69c/0x1000 kernel/workqueue.c:2273

worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
kthread+0x436/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
</TASK>


---

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#syz test: git://repo/address.git branch-or-commit-hash
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