INFO: task syz.2.764:12962 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.764 state:D stack:25032 pid:12962 tgid:12961 ppid:5809 task_flags:0x400140 flags:0x00080003
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x1480/0x50a0 kernel/sched/core.c:6863
__schedule_loop kernel/sched/core.c:6945 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6960
schedule_timeout+0x9a/0x270 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+0x2bf/0x5d0 kernel/sched/completion.c:153
kthread_flush_worker+0x10e/0x160 kernel/kthread.c:1559
__alloc_workqueue+0x1466/0x1b70 kernel/workqueue.c:5797
alloc_workqueue_noprof+0xd4/0x210 kernel/workqueue.c:5820
btrfs_init_workqueues+0x318/0x6c0 fs/btrfs/disk-io.c:1990
open_ctree+0x141d/0x3d20 fs/btrfs/disk-io.c:3426
btrfs_fill_super fs/btrfs/super.c:987 [inline]
btrfs_get_tree_super fs/btrfs/super.c:1951 [inline]
btrfs_get_tree_subvol fs/btrfs/super.c:2094 [inline]
btrfs_get_tree+0x1061/0x1920 fs/btrfs/super.c:2128
vfs_get_tree+0x92/0x2a0 fs/super.c:1759
fc_mount fs/namespace.c:1199 [inline]
do_new_mount_fc fs/namespace.c:3636 [inline]
do_new_mount+0x302/0xa10 fs/namespace.c:3712
do_mount fs/namespace.c:4035 [inline]
__do_sys_mount fs/namespace.c:4224 [inline]
__se_sys_mount+0x313/0x410 fs/namespace.c:4201
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fac666d0eea
RSP: 002b:00007fac6492de68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fac6492def0 RCX: 00007fac666d0eea
RDX: 0000200000005100 RSI: 0000200000000280 RDI: 00007fac6492deb0
RBP: 0000200000005100 R08: 00007fac6492def0 R09: 0000000000000810
R10: 0000000000000810 R11: 0000000000000246 R12: 0000200000000280
R13: 00007fac6492deb0 R14: 000000000000510e R15: 00002000000001c0
Showing all locks held in the system:
1 lock held by khungtaskd/38:
#0: ffffffff8d5aeba0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8d5aeba0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8d5aeba0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
4 locks held by kworker/u8:5/71:
3 locks held by udevd/5174:
2 locks held by getty/5563:
#0: ffff8880340fa0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003e8b2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x444/0x1400 drivers/tty/n_tty.c:2222
2 locks held by udevd/5927:
1 lock held by syz.2.764/12962:
#0: ffff8880516b00d0 (&type->s_umount_key#51/1){+.+.}-{4:4}, at: alloc_super+0x28c/0xab0 fs/super.c:344
3 locks held by syz.1.937/15508:
#0: ffff8880207c60d0 (&type->s_umount_key#62/1){+.+.}-{4:4}, at: alloc_super+0x28c/0xab0 fs/super.c:344
#1: ffff88805d553208 (&qinf->qi_tree_lock){+.+.}-{4:4}, at: xfs_qm_dquot_walk+0x141/0x4d0 fs/xfs/xfs_qm.c:77
#2: ffff88802697a388 (&dqp->q_qlock){+.+.}-{4:4}, at: xfs_dqlock fs/xfs/xfs_dquot.h:131 [inline]
#2: ffff88802697a388 (&dqp->q_qlock){+.+.}-{4:4}, at: xfs_qm_flush_one+0x8d/0x1e0 fs/xfs/xfs_qm.c:1469
3 locks held by syz.6.941/15556:
4 locks held by syz.4.938/15558:
3 locks held by syz.7.939/15560:
3 locks held by syz.0.940/15562:
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:332 [inline]
watchdog+0xf3c/0xf80 kernel/hung_task.c:495
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 71 Comm: kworker/u8:5 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: xfs-cil/loop1 xlog_cil_push_work
RIP: 0010:usage_skip kernel/locking/lockdep.c:2253 [inline]
RIP: 0010:__bfs kernel/locking/lockdep.c:1800 [inline]
RIP: 0010:__bfs_backwards kernel/locking/lockdep.c:1860 [inline]
RIP: 0010:check_irq_usage kernel/locking/lockdep.c:2796 [inline]
RIP: 0010:check_prev_add kernel/locking/lockdep.c:3169 [inline]
RIP: 0010:check_prevs_add kernel/locking/lockdep.c:3284 [inline]
RIP: 0010:validate_chain kernel/locking/lockdep.c:3908 [inline]
RIP: 0010:__lock_acquire+0x1879/0x2cf0 kernel/locking/lockdep.c:5237
Code: 80 e2 fa 80 78 2b 00 0f b6 c2 0f 44 c1 84 c0 0f 84 3d ff ff ff a8 0c 41 0f 94 44 24 2b 4d 8b 6c 24 10 41 0f b6 85 c6 00 00 00 <85> c0 74 5f 83 f8 01 0f 85 1b ff ff ff 83 3d 53 4c 19 17 00 0f 85
RSP: 0018:ffffc9000156eed8 EFLAGS: 00000002
RAX: 0000000000000000 RBX: 00000000000003cd RCX: 0000000000000008
RDX: 0000000000000008 RSI: ffff88801bbdc8b0 RDI: 00000000000003cd
RBP: 875afaf09de9f1d5 R08: ffffc9000156eea0 R09: 0000000000000020
R10: dffffc0000000000 R11: ffffffff819d2d20 R12: ffffffff953bbd18
R13: ffffffff9253eca0 R14: ffff88801bbdbc80 R15: 00000000000006df
FS: 0000000000000000(0000) GS:ffff888126e71000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff9f689da4 CR3: 0000000057f7c000 CR4: 00000000003526f0
Call Trace:
lock_acquire+0x117/0x340 kernel/locking/lockdep.c:5868
do_write_seqcount_begin_nested include/linux/seqlock.h:477 [inline]
do_write_seqcount_begin include/linux/seqlock.h:503 [inline]
psi_write_begin+0xab/0x160 kernel/sched/psi.c:183
psi_task_switch+0x53/0x880 kernel/sched/psi.c:933
psi_sched_switch kernel/sched/stats.h:220 [inline]
__schedule+0x24c0/0x50a0 kernel/sched/core.c:6857
preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:7047
preempt_schedule+0xae/0xc0 kernel/sched/core.c:7071
preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
class_preempt_destructor include/linux/preempt.h:468 [inline]
raw_spin_unlock_irqrestore_wake include/linux/sched/wake_q.h:99 [inline]
rtlock_slowlock kernel/locking/rtmutex.c:1896 [inline]
rtlock_lock kernel/locking/spinlock_rt.c:43 [inline]
__rt_spin_lock kernel/locking/spinlock_rt.c:49 [inline]
rt_spin_lock+0x2fb/0x3e0 kernel/locking/spinlock_rt.c:57
spin_lock include/linux/spinlock_rt.h:44 [inline]
___slab_alloc+0x12f/0x1400 mm/slub.c:4516
__slab_alloc+0xc6/0x1f0 mm/slub.c:4774
__slab_alloc_node mm/slub.c:4850 [inline]
slab_alloc_node mm/slub.c:5246 [inline]
kmem_cache_alloc_noprof+0xec/0x6d0 mm/slub.c:5265
xlog_ticket_alloc+0x3f/0x400 fs/xfs/xfs_log.c:3225
xlog_cil_ticket_alloc fs/xfs/xfs_log_cil.c:39 [inline]
xlog_cil_push_work+0x425/0x2560 fs/xfs/xfs_log_cil.c:1306
process_one_work kernel/workqueue.c:3257 [inline]
process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246