INFO: task syz.4.1371:19963 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.1371 state:D stack:25016 pid:19963 tgid:19960 ppid:15461 task_flags:0x400140 flags:0x00080003
Call Trace:
context_switch kernel/sched/core.c:5298 [inline]
__schedule+0x1553/0x5240 kernel/sched/core.c:6911
__schedule_loop kernel/sched/core.c:6993 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7008
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:1579
__alloc_workqueue+0xfed/0x1e90 kernel/workqueue.c:5861
alloc_workqueue_noprof+0xe3/0x210 kernel/workqueue.c:5884
btrfs_alloc_ordered_workqueue+0x1c3/0x290 fs/btrfs/async-thread.c:140
btrfs_init_workqueues+0x192/0x680 fs/btrfs/disk-io.c:1942
open_ctree+0x1598/0x4220 fs/btrfs/disk-io.c:3458
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:3763 [inline]
do_new_mount+0x341/0xd30 fs/namespace.c:3839
do_mount fs/namespace.c:4172 [inline]
__do_sys_mount fs/namespace.c:4361 [inline]
__se_sys_mount+0x31d/0x420 fs/namespace.c:4338
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: 0033:0x7f6a6c2cda0a
RSP: 002b:00007f6a6a525e58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f6a6a525ee0 RCX: 00007f6a6c2cda0a
RDX: 00002000000051c0 RSI: 0000200000005200 RDI: 00007f6a6a525ea0
RBP: 00002000000051c0 R08: 00007f6a6a525ee0 R09: 0000000001204408
R10: 0000000001204408 R11: 0000000000000246 R12: 0000200000005200
R13: 00007f6a6a525ea0 R14: 00000000000051ab R15: 00002000000003c0
Showing all locks held in the system:
1 lock held by khungtaskd/38:
#0: ffffffff8ddcba80 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#0: ffffffff8ddcba80 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#0: ffffffff8ddcba80 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by getty/5556:
#0: ffff88803774f0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003e832e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13c0 drivers/tty/n_tty.c:2211
4 locks held by syz-executor/5796:
1 lock held by udevd/15264:
4 locks held by udevd/17512:
1 lock held by syz.4.1371/19963:
#0: ffff88806670c0d0 (&type->s_umount_key#53/1){+.+.}-{4:4}, at: alloc_super+0x28c/0xac0 fs/super.c:345
5 locks held by kworker/u8:13/21463:
1 lock held by syz.5.1632/21941:
2 locks held by udevadm/21946:
3 locks held by syz.0.1637/21954:
2 locks held by syz.3.1636/21958:
2 locks held by syz.1.1639/21965:
2 locks held by cmp/21967:
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
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+0xfd9/0x1030 kernel/hung_task.c:515
kthread+0x388/0x470 kernel/kthread.c:436
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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 21958 Comm: syz.3.1636 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline]
RIP: 0010:rcu_is_watching+0x10/0xb0 kernel/rcu/tree.c:752
Code: 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 41 57 41 56 53 65 ff 05 e0 f5 a4 10 5b f2 79 09 89 c3 83 f8 08 73 65 49 bf 00 00 00 00 00 fc ff df
RSP: 0018:ffffc90003eef7a0 EFLAGS: 00000083
RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff81cc643c
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8f6a5db0
RBP: ffffc90003eef8c0 R08: ffffffff8f6a5db7 R09: 1ffffffff1ed4bb6
R10: dffffc0000000000 R11: fffffbfff1ed4bb7 R12: 1ffff920007ddf09
R13: dffffc0000000000 R14: ffff8880b8833fb8 R15: ffffc90003eef840
FS: 00007facd0cc66c0(0000) GS:ffff888126339000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5f1cb09000 CR3: 0000000067c64000 CR4: 00000000003526f0
Call Trace:
trace_irq_disable+0x3b/0x150 include/trace/events/preemptirq.h:36
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:130 [inline]
_raw_spin_lock_irqsave+0x1a/0x60 kernel/locking/spinlock.c:162
rtlock_slowlock kernel/locking/rtmutex.c:1894 [inline]
rtlock_lock kernel/locking/spinlock_rt.c:43 [inline]
__rt_spin_lock kernel/locking/spinlock_rt.c:49 [inline]
rt_spin_lock+0x157/0x400 kernel/locking/spinlock_rt.c:57
spin_lock include/linux/spinlock_rt.h:45 [inline]
__folio_batch_add_and_move+0x283/0xa90 mm/swap.c:-1
shmem_alloc_and_add_folio mm/shmem.c:2031 [inline]
shmem_get_folio_gfp+0xb73/0x1a80 mm/shmem.c:2567
shmem_get_folio mm/shmem.c:2673 [inline]
shmem_write_begin+0x166/0x320 mm/shmem.c:3327
generic_perform_write+0x2af/0x8b0 mm/filemap.c:4319
shmem_file_write_iter+0xfb/0x120 mm/shmem.c:3502
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x629/0xba0 fs/read_write.c:688
ksys_write+0x156/0x270 fs/read_write.c:740
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: 0033:0x7facd2a2cfce
Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08
RSP: 002b:00007facd0cc5da8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007facd0cc66c0 RCX: 00007facd2a2cfce
RDX: 0000000001000000 RSI: 00007facc88a6000 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 00007facd0cc5ee0 R14: 00007facd0cc5ea0 R15: 00007facc88a6000