INFO: task syz.2.1901:12659 blocked for more than 143 seconds.
      Not tainted 6.13.0-syzkaller-08265-g9c5968db9e62 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.1901      state:D stack:28416 pid:12659 tgid:12658 ppid:5822   task_flags:0x400040 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5377 [inline]
 __schedule+0xf43/0x5890 kernel/sched/core.c:6764
 __schedule_loop kernel/sched/core.c:6841 [inline]
 schedule+0xe7/0x350 kernel/sched/core.c:6856
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6913
 __mutex_lock_common kernel/locking/mutex.c:662 [inline]
 __mutex_lock+0x6bd/0xb10 kernel/locking/mutex.c:730
 bdev_open+0x41a/0xe20 block/bdev.c:903
 blkdev_open+0x272/0x3f0 block/fops.c:652
 do_dentry_open+0x735/0x1c40 fs/open.c:955
 vfs_open+0x82/0x3f0 fs/open.c:1085
 do_open fs/namei.c:3828 [inline]
 path_openat+0x1e88/0x2d80 fs/namei.c:3987
 do_filp_open+0x20c/0x470 fs/namei.c:4014
 do_sys_openat2+0x17a/0x1e0 fs/open.c:1427
 do_sys_open fs/open.c:1442 [inline]
 __do_sys_openat fs/open.c:1458 [inline]
 __se_sys_openat fs/open.c:1453 [inline]
 __x64_sys_openat+0x175/0x210 fs/open.c:1453
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3cf9f8b710
RSP: 002b:00007f3cfad23b70 EFLAGS: 00000293 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f3cf9f8b710
RDX: 0000000000000000 RSI: 00007f3cfad23c10 RDI: 00000000ffffff9c
RBP: 00007f3cfad23c10 R08: 0000000000000000 R09: 002364626e2f7665
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f3cfa1a5fa0 R15: 00007fffa812cac8
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/30:
 #0: ffffffff8e1be000 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 #0: ffffffff8e1be000 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8e1be000 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x7f/0x390 kernel/locking/lockdep.c:6746
3 locks held by kworker/u8:6/3526:
2 locks held by getty/5579:
 #0: ffff8880372710a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
 #1: ffffc90002fde2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0xfba/0x1480 drivers/tty/n_tty.c:2211
1 lock held by udevd/6477:
 #0: ffff8881443694c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0x41a/0xe20 block/bdev.c:903
1 lock held by udevd/6620:
 #0: ffff888025c134c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0x41a/0xe20 block/bdev.c:903
1 lock held by syz.2.1901/12659:
 #0: ffff888025c134c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0x41a/0xe20 block/bdev.c:903
1 lock held by syz.0.2182/13711:
 #0: ffff8881443694c8 (&disk->open_mutex){+.+.}-{4:4}, at: bdev_open+0x41a/0xe20 block/bdev.c:903
2 locks held by syz.4.2381/14440:

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.13.0-syzkaller-08265-g9c5968db9e62 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:236 [inline]
 watchdog+0xf62/0x12b0 kernel/hung_task.c:399
 kthread+0x3af/0x750 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 81 Comm: kworker/u8:4 Not tainted 6.13.0-syzkaller-08265-g9c5968db9e62 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Workqueue: events_unbound idle_cull_fn
RIP: 0010:arch_clear_bit arch/x86/include/asm/bitops.h:75 [inline]
RIP: 0010:clear_bit include/asm-generic/bitops/instrumented-atomic.h:42 [inline]
RIP: 0010:kthread_set_per_cpu+0x11e/0x170 kernel/kthread.c:676
Code: 00 48 89 df e8 53 dd 97 00 f0 80 0b 01 5b 5d 41 5c 41 5d e9 14 c0 34 00 e8 0f c0 34 00 be 08 00 00 00 48 89 df e8 32 dd 97 00 <f0> 80 23 fe 5b 5d 41 5c 41 5d e9 f3 bf 34 00 e8 ee bf 34 00 90 0f
RSP: 0018:ffffc900021bfaf8 EFLAGS: 00010246
RAX: 0000000000000001 RBX: ffff888033679800 RCX: ffffffff8184eeae
RDX: ffffed10066cf301 RSI: 0000000000000008 RDI: ffff888033679800
RBP: 0000000004000000 R08: 0000000000000001 R09: ffffed10066cf300
R10: ffff888033679807 R11: 0000000000000005 R12: 00000000ffffffff
R13: 0000000000200000 R14: ffffc900021bfbe8 R15: ffff888034597100
FS:  0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7455978ab8 CR3: 000000002a594000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 unbind_worker+0x83/0x1f0 kernel/workqueue.c:2703
 detach_worker+0x66/0x200 kernel/workqueue.c:2715
 detach_dying_workers kernel/workqueue.c:2849 [inline]
 idle_cull_fn+0x1e9/0x450 kernel/workqueue.c:2977
 process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3236
 process_scheduled_works kernel/workqueue.c:3317 [inline]
 worker_thread+0x6c8/0xf00 kernel/workqueue.c:3398
 kthread+0x3af/0x750 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>