INFO: task syz.0.19:5315 blocked for more than 143 seconds.
      Not tainted 5.15.179-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.19        state:D stack:25920 pid: 5315 ppid:  5188 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5029 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6375
 schedule+0x11b/0x1f0 kernel/sched/core.c:6458
 schedule_timeout+0xac/0x300 kernel/time/timer.c:1890
 do_wait_for_common+0x2d9/0x480 kernel/sched/completion.c:85
 __wait_for_common kernel/sched/completion.c:106 [inline]
 wait_for_common kernel/sched/completion.c:117 [inline]
 wait_for_completion+0x48/0x60 kernel/sched/completion.c:138
 kthread_stop+0x178/0x580 kernel/kthread.c:666
 ext4_stop_mmpd+0x43/0xb0 fs/ext4/mmp.c:263
 ext4_fill_super+0x6d67/0xa110 fs/ext4/super.c:5089
 mount_bdev+0x2c9/0x3f0 fs/super.c:1400
 legacy_get_tree+0xeb/0x180 fs/fs_context.c:611
 vfs_get_tree+0x88/0x270 fs/super.c:1530
 do_new_mount+0x2ba/0xb40 fs/namespace.c:3012
 do_mount fs/namespace.c:3355 [inline]
 __do_sys_mount fs/namespace.c:3563 [inline]
 __se_sys_mount+0x2d5/0x3c0 fs/namespace.c:3540
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f9359aaa90a
RSP: 002b:00007f9358d19e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f9358d19ef0 RCX: 00007f9359aaa90a
RDX: 0000400000000040 RSI: 0000400000000000 RDI: 00007f9358d19eb0
RBP: 0000400000000040 R08: 00007f9358d19ef0 R09: 0000000003010008
R10: 0000000003010008 R11: 0000000000000246 R12: 0000400000000000
R13: 00007f9358d19eb0 R14: 0000000000000538 R15: 0000400000000340
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffffffff8cb1f4e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
2 locks held by getty/3933:
 #0: ffff88814ccd4098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc900026362e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6af/0x1db0 drivers/tty/n_tty.c:2158
1 lock held by syz.0.19/5315:
 #0: ffff8880238440e0 (&type->s_umount_key#28/1){+.+.}-{3:3}, at: alloc_super+0x210/0x940 fs/super.c:229
1 lock held by syz.1.22/5365:
 #0: ffff88807e7960e0 (&type->s_umount_key#28/1){+.+.}-{3:3}, at: alloc_super+0x210/0x940 fs/super.c:229
1 lock held by syz.2.25/5388:
 #0: ffff8880680c40e0 (&type->s_umount_key#28/1){+.+.}-{3:3}, at: alloc_super+0x210/0x940 fs/super.c:229
1 lock held by syz.3.27/5408:
 #0: ffff88807ebec0e0 (&type->s_umount_key#28/1){+.+.}-{3:3}, at: alloc_super+0x210/0x940 fs/super.c:229
1 lock held by syz.4.35/5453:
 #0: ffff88807e5ac0e0 (&type->s_umount_key#28/1){+.+.}-{3:3}, at: alloc_super+0x210/0x940 fs/super.c:229
1 lock held by syz.5.49/5515:
 #0: ffff888077a160e0 (&type->s_umount_key#28/1){+.+.}-{3:3}, at: alloc_super+0x210/0x940 fs/super.c:229
1 lock held by syz.6.53/5547:
 #0: ffff888059c5a0e0 (&type->s_umount_key#28/1){+.+.}-{3:3}, at: alloc_super+0x210/0x940 fs/super.c:229
1 lock held by syz.7.57/5585:
 #0: ffff8880200280e0 (&type->s_umount_key#28/1){+.+.}-{3:3}, at: alloc_super+0x210/0x940 fs/super.c:229
1 lock held by syz.8.59/5611:
 #0: ffff88807d78a0e0 (&type->s_umount_key#28/1){+.+.}-{3:3}, at: alloc_super+0x210/0x940 fs/super.c:229

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

NMI backtrace for cpu 0
CPU: 0 PID: 27 Comm: khungtaskd Not tainted 5.15.179-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x46a/0x4a0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x181/0x2a0 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+0xe72/0xeb0 kernel/hung_task.c:369
 kthread+0x3f6/0x4f0 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: 3536 Comm: klogd Not tainted 5.15.179-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
RIP: 0010:unwind_get_return_address+0x52/0x80 arch/x86/kernel/unwind_orc.c:323
Code: 83 c3 48 49 89 df 49 c1 ef 03 43 80 3c 37 00 74 08 48 89 df e8 ff d6 91 00 48 8b 3b e8 47 23 1c 00 85 c0 74 14 43 80 3c 37 00 <74> 08 48 89 df e8 e4 d6 91 00 48 8b 03 eb 02 31 c0 5b 41 5e 41 5f
RSP: 0000:ffffc90002e1f640 EFLAGS: 00000046
RAX: 0000000000000001 RBX: ffffc90002e1f6a8 RCX: 0000000080000101
RDX: dffffc0000000000 RSI: ffffc90002e1fbf0 RDI: ffffffff816f5068
RBP: ffffc90002e1f6f0 R08: ffffc90002e1fbf0 R09: ffffc90002e1f6b0
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff88807dfed940
R13: ffffffff816e2db0 R14: dffffc0000000000 R15: 1ffff920005c3ed5
FS:  00007ff79b416380(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1506a0f5b0 CR3: 000000002a9f6000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 arch_stack_walk+0xf3/0x140 arch/x86/kernel/stacktrace.c:26
 stack_trace_save+0x113/0x1c0 kernel/stacktrace.c:122
 kasan_save_stack+0x36/0x60 mm/kasan/common.c:38
 kasan_record_aux_stack+0xba/0x100 mm/kasan/generic.c:348
 insert_work+0x54/0x3e0 kernel/workqueue.c:1366
 __queue_work+0x963/0xd00 kernel/workqueue.c:1532
 call_timer_fn+0x16d/0x560 kernel/time/timer.c:1451
 expire_timers kernel/time/timer.c:1491 [inline]
 __run_timers+0x6a8/0x890 kernel/time/timer.c:1767
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1780
 handle_softirqs+0x3a7/0x930 kernel/softirq.c:558
 __do_softirq kernel/softirq.c:592 [inline]
 invoke_softirq kernel/softirq.c:432 [inline]
 __irq_exit_rcu+0x157/0x240 kernel/softirq.c:641
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:653
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0x52/0xc0 arch/x86/kernel/apic/apic.c:1108
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0033:0x7ff79b50bde8
Code: 15 9d 5a 13 00 48 8d 05 fe 67 13 00 48 89 f9 41 54 48 29 d0 48 29 d1 49 89 fc 48 39 c8 77 05 e8 a3 e2 ff ff 4c 89 e0 41 5c c3 <f6> 07 80 0f 84 6f 01 00 00 41 55 48 8d 05 57 ff ff ff 41 54 4c 8d
RSP: 002b:00007fffacedd758 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00007ff79b6420a0 RCX: 00007ff79b60f7e8
RDX: 00007fffacedd798 RSI: 0000000000000000 RDI: 00005654c22e2910
RBP: 00005654c22e2910 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000008 R11: 0000000000000000 R12: 0000000000000000
R13: 00007ff79b706212 R14: 00007fffacedd878 R15: 0000000000000000
 </TASK>