INFO: task syz.5.707:12902 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.5.707 state:D stack:25624 pid:12902 tgid:12901 ppid:7659 task_flags:0x400140 flags:0x00080003
Call Trace:
context_switch kernel/sched/core.c:5295 [inline]
__schedule+0x14de/0x5210 kernel/sched/core.c:6907
__schedule_loop kernel/sched/core.c:6989 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7004
schedule_timeout+0xc3/0x2c0 kernel/time/sleep_timeout.c:75
do_wait_for_common kernel/sched/completion.c:100 [inline]
__wait_for_common kernel/sched/completion.c:121 [inline]
wait_for_common kernel/sched/completion.c:132 [inline]
wait_for_completion+0x2cc/0x5e0 kernel/sched/completion.c:153
kthread_flush_worker+0x138/0x1a0 kernel/kthread.c:1611
__alloc_workqueue+0xfed/0x1e90 kernel/workqueue.c:5860
alloc_workqueue_noprof+0xe3/0x210 kernel/workqueue.c:5883
btrfs_alloc_workqueue+0x1ec/0x2d0 fs/btrfs/async-thread.c:112
btrfs_init_workqueues+0xb0/0x680 fs/btrfs/disk-io.c:1920
open_ctree+0x1598/0x4220 fs/btrfs/disk-io.c:3448
btrfs_fill_super fs/btrfs/super.c:981 [inline]
btrfs_get_tree_super fs/btrfs/super.c:1944 [inline]
btrfs_get_tree_subvol fs/btrfs/super.c:2087 [inline]
btrfs_get_tree+0x1061/0x1930 fs/btrfs/super.c:2121
vfs_get_tree+0x92/0x2a0 fs/super.c:1754
fc_mount fs/namespace.c:1193 [inline]
do_new_mount_fc fs/namespace.c:3760 [inline]
do_new_mount+0x341/0xd30 fs/namespace.c:3836
do_mount fs/namespace.c:4159 [inline]
__do_sys_mount fs/namespace.c:4348 [inline]
__se_sys_mount+0x31d/0x420 fs/namespace.c:4325
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f426712d20a
RSP: 002b:00007f4265385e58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f4265385ee0 RCX: 00007f426712d20a
RDX: 00002000000004c0 RSI: 00002000000015c0 RDI: 00007f4265385ea0
RBP: 00002000000004c0 R08: 00007f4265385ee0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00002000000015c0
R13: 00007f4265385ea0 R14: 000000000000559e R15: 00002000000000c0
Showing all locks held in the system:
2 locks held by kworker/u8:0/12:
#0: ffff88813fe74138 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3250 [inline]
#0: ffff88813fe74138 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_scheduled_works+0x9d4/0x17a0 kernel/workqueue.c:3358
#1: ffffc90000117c40 ((reaper_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
#1: ffffc90000117c40 ((reaper_work).work){+.+.}-{0:0}, at: process_scheduled_works+0xa0f/0x17a0 kernel/workqueue.c:3358
2 locks held by kworker/u8:1/13:
#0: ffff88813fe74138 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3250 [inline]
#0: ffff88813fe74138 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_scheduled_works+0x9d4/0x17a0 kernel/workqueue.c:3358
#1: ffffc90000127c40 (connector_reaper_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
#1: ffffc90000127c40 (connector_reaper_work){+.+.}-{0:0}, at: process_scheduled_works+0xa0f/0x17a0 kernel/workqueue.c:3358
1 lock held by khungtaskd/37:
#0: ffffffff8dbcd480 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#0: ffffffff8dbcd480 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#0: ffffffff8dbcd480 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by getty/5554:
#0: ffff888036d560a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc900042062e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13c0 drivers/tty/n_tty.c:2211
3 locks held by udevd/7661:
1 lock held by udevd/7801:
3 locks held by kworker/u8:4/10124:
1 lock held by syz.5.707/12902:
#0: ffff888019fca0d0 (&type->s_umount_key#67/1){+.+.}-{4:4}, at: alloc_super+0x28c/0xac0 fs/super.c:345
2 locks held by syz.3.910/15327:
2 locks held by syz.4.912/15334:
3 locks held by syz.8.914/15336:
4 locks held by syz.6.913/15338:
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:161 [inline]
__sys_info lib/sys_info.c:157 [inline]
sys_info+0x135/0x170 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline]
watchdog+0xf90/0xfe0 kernel/hung_task.c:515
kthread+0x388/0x470 kernel/kthread.c:467
ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 7801 Comm: udevd Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
RIP: 0010:arch_irqs_disabled_flags arch/x86/include/asm/irqflags.h:146 [inline]
RIP: 0010:lockdep_hardirqs_off+0x30/0xd0 kernel/locking/lockdep.c:4502
Code: 53 83 3d f2 e6 36 04 00 0f 84 84 00 00 00 48 89 fb 65 8b 05 22 5c 16 07 a9 00 00 f0 00 74 5c 83 3d 44 b0 21 0e 00 75 09 9c 58 00 02 00 00 75 6a 65 8b 05 0a 9e 16 07 85 c0 74 56 65 4c 8b 35
RSP: 0018:ffffc900041772e0 EFLAGS: 00000046
RAX: 0000000000000046 RBX: ffffffff8b15d30a RCX: 0000000000000046
RDX: 0000000000000001 RSI: ffffffff8d3a9f6a RDI: ffffffff8b861580
RBP: ffffc90004177410 R08: ffffffff8b14a050 R09: ffffffff8dbcd480
R10: 0000000000000000 R11: fffff940003fa609 R12: dffffc0000000000
R13: 1ffff9200082ee6c R14: ffff88801aead298 R15: ffff88801aead298
FS: 00007ff925bfb880(0000) GS:ffff888126695000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2d7f8bc000 CR3: 000000003025e000 CR4: 00000000003526f0
Call Trace:
trace_hardirqs_off+0x12/0x40 kernel/trace/trace_preemptirq.c:104
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:130 [inline]
_raw_spin_lock_irqsave+0x1a/0x60 kernel/locking/spinlock.c:162
rt_mutex_slowunlock+0xbf/0x8b0 kernel/locking/rtmutex.c:1417
spin_unlock_irqrestore include/linux/spinlock_rt.h:129 [inline]
unlock_page_lruvec_irqrestore include/linux/memcontrol.h:1504 [inline]
folios_put_refs+0x506/0x680 mm/swap.c:994
free_pages_and_swap_cache+0x537/0x5b0 mm/swap_state.c:357
__tlb_batch_free_encoded_pages mm/mmu_gather.c:137 [inline]
tlb_batch_pages_flush mm/mmu_gather.c:150 [inline]
tlb_flush_mmu_free mm/mmu_gather.c:398 [inline]
tlb_flush_mmu+0x6d3/0xa30 mm/mmu_gather.c:405
tlb_finish_mmu+0xf9/0x230 mm/mmu_gather.c:530
vms_clear_ptes+0x44d/0x570 mm/vma.c:1278
vms_complete_munmap_vmas+0x205/0x890 mm/vma.c:1320
do_vmi_align_munmap+0x3bd/0x4d0 mm/vma.c:1579
do_vmi_munmap+0x252/0x2d0 mm/vma.c:1627
__vm_munmap+0x22c/0x3d0 mm/vma.c:3247
__do_sys_munmap mm/mmap.c:1077 [inline]
__se_sys_munmap mm/mmap.c:1074 [inline]
__x64_sys_munmap+0x60/0x70 mm/mmap.c:1074
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff925d60097
Code: 73 01 c3 48 8b 0d 61 2d 0d 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 0b 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 31 2d 0d 00 f7 d8 64 89 01 48
RSP: 002b:00007ffd2efa8408 EFLAGS: 00000246 ORIG_RAX: 000000000000000b
RAX: ffffffffffffffda RBX: 0000563883023820 RCX: 00007ff925d60097
RDX: 0000563883023868 RSI: 0000000000000200 RDI: 00007ff92529c000
RBP: 0000000000000013 R08: 000056388303b5e0 R09: 0000000000000003
R10: 0000000000000040 R11: 0000000000000246 R12: 00005638830250b0
R13: 00007ff92643f39c R14: 0000000000002600 R15: 0000000000000009