INFO: task syz.4.3669:1780 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.3669 state:D stack:25528 pid:1780 tgid:1778 ppid:25534 task_flags:0x400140 flags:0x00080003
Call Trace:
context_switch kernel/sched/core.c:5388 [inline]
__schedule+0x16ec/0x5620 kernel/sched/core.c:7189
__schedule_loop kernel/sched/core.c:7268 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7283
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+0x15f5/0x1f40 kernel/workqueue.c:5909
alloc_workqueue_va kernel/workqueue.c:5931 [inline]
alloc_workqueue_noprof+0xe3/0x210 kernel/workqueue.c:5947
btrfs_init_workqueues+0x3de/0x680 fs/btrfs/disk-io.c:1968
open_ctree+0x1598/0x4190 fs/btrfs/disk-io.c:3444
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+0x1061/0x1910 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:3758 [inline]
do_new_mount+0x341/0xd30 fs/namespace.c:3834
do_mount fs/namespace.c:4167 [inline]
__do_sys_mount fs/namespace.c:4383 [inline]
__se_sys_mount+0x31d/0x420 fs/namespace.c:4360
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f06bdc4e0ca
RSP: 002b:00007f06bbe9de58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f06bbe9dee0 RCX: 00007f06bdc4e0ca
RDX: 0000200000000000 RSI: 0000200000005600 RDI: 00007f06bbe9dea0
RBP: 0000200000000000 R08: 00007f06bbe9dee0 R09: 0000000000010001
R10: 0000000000010001 R11: 0000000000000246 R12: 0000200000005600
R13: 00007f06bbe9dea0 R14: 000000000000559e R15: 0000200000000500
Showing all locks held in the system:
1 lock held by khungtaskd/37:
#0: ffffffff8dfc8080 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8dfc8080 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#0: ffffffff8dfc8080 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
5 locks held by kworker/u8:3/56:
5 locks held by kworker/u8:9/1186:
9 locks held by kworker/u8:11/1394:
2 locks held by getty/5360:
#0: ffff8880326b00a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003cc62e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13a0 drivers/tty/n_tty.c:2211
4 locks held by syz-executor/22561:
1 lock held by syz.4.3669/1780:
#0: ffff8880625f20d0 (&type->s_umount_key#58/1){+.+.}-{4:4}, at: alloc_super+0x28c/0xac0 fs/super.c:345
=============================================
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 04/18/2026
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:162 [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:353 [inline]
watchdog+0xfd3/0x1030 kernel/hung_task.c:561
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 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: 1186 Comm: kworker/u8:9 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: events_unbound nsim_dev_trap_report_work
RIP: 0010:trace_hardirqs_off+0xa/0x40 kernel/trace/trace_preemptirq.c:104
Code: 3f ff ff ff 66 66 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 53 48 8b 5c 24 08 <48> 89 df e8 de 9c 50 09 65 8b 05 77 5f 9f 10 85 c0 74 07 5b c3 cc
RSP: 0018:ffffc900062f7818 EFLAGS: 00000006
RAX: 1ffff92000c5ef15 RBX: ffffffff8b20cd0a RCX: 0000000000000046
RDX: 0000000000000005 RSI: ffffffff8d865ad1 RDI: ffff8880b8940680
RBP: ffffc900062f7928 R08: ffffffff8b1faf2c R09: ffffffff8dfc8080
R10: 0000000000000000 R11: fffffbfff1f1209f R12: dffffc0000000000
R13: 1ffff92000c5ef10 R14: ffff8880b8940680 R15: ffff8880b8940680
FS: 0000000000000000(0000) GS:ffff888126271000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055f4f1ec7660 CR3: 000000000ddb6000 CR4: 00000000003526f0
Call Trace:
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:130 [inline]
_raw_spin_lock_irqsave+0x1a/0x60 kernel/locking/spinlock.c:166
rt_mutex_slowunlock+0xbf/0x8b0 kernel/locking/rtmutex.c:1426
spin_unlock include/linux/spinlock_rt.h:109 [inline]
alloc_from_pcs mm/slub.c:4771 [inline]
slab_alloc_node mm/slub.c:4883 [inline]
__do_kmalloc_node mm/slub.c:5294 [inline]
__kmalloc_node_track_caller_noprof+0x490/0x7e0 mm/slub.c:5407
kmalloc_reserve net/core/skbuff.c:635 [inline]
__alloc_skb+0x2c1/0x7d0 net/core/skbuff.c:713
alloc_skb include/linux/skbuff.h:1383 [inline]
nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:819 [inline]
nsim_dev_trap_report drivers/net/netdevsim/dev.c:876 [inline]
nsim_dev_trap_report_work+0x29f/0xbd0 drivers/net/netdevsim/dev.c:922
process_one_work kernel/workqueue.c:3314 [inline]
process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397
worker_thread+0xa53/0xfc0 kernel/workqueue.c:3478
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245