INFO: task kworker/u4:11:11619 blocked for more than 143 seconds.
      Not tainted 5.15.0-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:11   state:D stack:23888 pid:11619 ppid:     2 flags:0x00004000
Workqueue: nbd-del nbd_dev_remove_work
Call Trace:
 
 context_switch kernel/sched/core.c:4969 [inline]
 __schedule+0xa9a/0x4940 kernel/sched/core.c:6250
 schedule+0xd2/0x260 kernel/sched/core.c:6323
 blk_mq_freeze_queue_wait+0x112/0x160 block/blk-mq.c:178
 del_gendisk+0x598/0x860 block/genhd.c:623
 nbd_dev_remove+0x3c/0xf0 drivers/block/nbd.c:252
 process_one_work+0x9b2/0x1690 kernel/workqueue.c:2298
 worker_thread+0x658/0x11f0 kernel/workqueue.c:2445
 kthread+0x405/0x4f0 kernel/kthread.c:327
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 
Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffffffff8bb83b60 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6458
1 lock held by in:imklog/6214:
2 locks held by agetty/6440:
 #0: ffff8880139ac098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:252
 #1: ffffc90002afc2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xcf0/0x1230 drivers/tty/n_tty.c:2113
2 locks held by agetty/6441:
 #0: ffff88801a251098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:252
 #1: ffffc9000294b2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xcf0/0x1230 drivers/tty/n_tty.c:2113
2 locks held by kworker/u4:11/11619:
 #0: ffff88801a8d7938 ((wq_completion)nbd-del){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: ffff88801a8d7938 ((wq_completion)nbd-del){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline]
 #0: ffff88801a8d7938 ((wq_completion)nbd-del){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1198 [inline]
 #0: ffff88801a8d7938 ((wq_completion)nbd-del){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:635 [inline]
 #0: ffff88801a8d7938 ((wq_completion)nbd-del){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:662 [inline]
 #0: ffff88801a8d7938 ((wq_completion)nbd-del){+.+.}-{0:0}, at: process_one_work+0x896/0x1690 kernel/workqueue.c:2269
 #1: ffffc90002a6fdb0 ((work_completion)(&nbd->remove_work)){+.+.}-{0:0}, at: process_one_work+0x8ca/0x1690 kernel/workqueue.c:2273
1 lock held by syz-executor.2/22993:
 #0: ffff88807f474460 (sb_writers#5){.+.+}-{0:0}, at: __do_sys_sendfile64 fs/read_write.c:1310 [inline]
 #0: ffff88807f474460 (sb_writers#5){.+.+}-{0:0}, at: __se_sys_sendfile64 fs/read_write.c:1296 [inline]
 #0: ffff88807f474460 (sb_writers#5){.+.+}-{0:0}, at: __x64_sys_sendfile64+0x1cc/0x210 fs/read_write.c:1296
=============================================
NMI backtrace for cpu 1
CPU: 1 PID: 27 Comm: khungtaskd Not tainted 5.15.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:105
 nmi_trigger_cpumask_backtrace+0x1ae/0x220 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:210 [inline]
 watchdog+0xc1d/0xf50 kernel/hung_task.c:295
 kthread+0x405/0x4f0 kernel/kthread.c:327
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 22166 Comm: kworker/0:13 Not tainted 5.15.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events nsim_dev_trap_report_work
RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:27 [inline]
RIP: 0010:check_kcov_mode kernel/kcov.c:166 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x60 kernel/kcov.c:200
Code: 48 89 ef 5d e9 a1 19 46 00 5d be 03 00 00 00 e9 a6 0d 63 02 66 0f 1f 44 00 00 48 8b be b0 01 00 00 e8 b4 ff ff ff 31 c0 c3 90 <65> 8b 05 09 89 8a 7e 89 c1 48 8b 34 24 81 e1 00 01 00 00 65 48 8b
RSP: 0018:ffffc90004f9fb88 EFLAGS: 00000093
RAX: 0000000000000000 RBX: ffff8880b9c28280 RCX: 0000000000000000
RDX: ffff8880180e8000 RSI: ffffffff8166f33b RDI: 0000000000000003
RBP: ffff888022a88048 R08: 0000000000028280 R09: 0000000000000003
R10: ffffffff8166f527 R11: 0000000000000000 R12: ffff8880b9c282c8
R13: ffff8880b9c28280 R14: 0000000000000000 R15: 00000000ffffffff
FS:  0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f18008c9000 CR3: 0000000030be6000 CR4: 0000000000350ef0
Call Trace:
 
 debug_timer_activate kernel/time/timer.c:729 [inline]
 __mod_timer+0x76e/0xe30 kernel/time/timer.c:1050
 __queue_delayed_work+0x1a7/0x270 kernel/workqueue.c:1678
 queue_delayed_work_on+0x105/0x120 kernel/workqueue.c:1703
 process_one_work+0x9b2/0x1690 kernel/workqueue.c:2298
 worker_thread+0x658/0x11f0 kernel/workqueue.c:2445
 kthread+0x405/0x4f0 kernel/kthread.c:327
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 
----------------
Code disassembly (best guess):
   0:	48 89 ef             	mov    %rbp,%rdi
   3:	5d                   	pop    %rbp
   4:	e9 a1 19 46 00       	jmpq   0x4619aa
   9:	5d                   	pop    %rbp
   a:	be 03 00 00 00       	mov    $0x3,%esi
   f:	e9 a6 0d 63 02       	jmpq   0x2630dba
  14:	66 0f 1f 44 00 00    	nopw   0x0(%rax,%rax,1)
  1a:	48 8b be b0 01 00 00 	mov    0x1b0(%rsi),%rdi
  21:	e8 b4 ff ff ff       	callq  0xffffffda
  26:	31 c0                	xor    %eax,%eax
  28:	c3                   	retq
  29:	90                   	nop
* 2a:	65 8b 05 09 89 8a 7e 	mov    %gs:0x7e8a8909(%rip),%eax        # 0x7e8a893a <-- trapping instruction
  31:	89 c1                	mov    %eax,%ecx
  33:	48 8b 34 24          	mov    (%rsp),%rsi
  37:	81 e1 00 01 00 00    	and    $0x100,%ecx
  3d:	65                   	gs
  3e:	48                   	rex.W
  3f:	8b                   	.byte 0x8b