INFO: task syz.6.1348:10552 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.1348 state:D stack:27128 pid:10552 tgid:10552 ppid:8088 task_flags:0x400040 flags:0x00080003
Call Trace:
context_switch kernel/sched/core.c:5388 [inline]
__schedule+0x1295/0x67a0 kernel/sched/core.c:7189
__schedule_loop kernel/sched/core.c:7268 [inline]
schedule+0xdd/0x390 kernel/sched/core.c:7283
request_wait_answer+0x55e/0x860 fs/fuse/dev.c:590
__fuse_request_send fs/fuse/dev.c:604 [inline]
__fuse_simple_request+0x45b/0xf00 fs/fuse/dev.c:699
fuse_simple_request fs/fuse/fuse_i.h:1262 [inline]
fuse_flush+0x4e4/0x6b0 fs/fuse/file.c:500
filp_flush+0xe7/0x190 fs/open.c:1467
filp_close+0x1c/0x30 fs/open.c:1480
__range_close+0x137/0x7a0 fs/file.c:794
__do_sys_close_range fs/file.c:855 [inline]
__se_sys_close_range fs/file.c:819 [inline]
__x64_sys_close_range+0x3ce/0x5d0 fs/file.c:819
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd76bb9ce59
RSP: 002b:00007ffd811960d8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: ffffffffffffffda RBX: 00007ffd811961c0 RCX: 00007fd76bb9ce59
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 0000000000064daf R08: 0000000000000001 R09: 0000000000000000
R10: 0000001b2d220000 R11: 0000000000000246 R12: 00007ffd81196200
R13: 00007fd76be15fac R14: 0000000000065238 R15: 00007fd76be15fa0
Showing all locks held in the system:
1 lock held by khungtaskd/30:
#0: ffffffff8e7e5620 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8e7e5620 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#0: ffffffff8e7e5620 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775
6 locks held by kworker/1:1/46:
#0: ffff8880232c6140 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12d6/0x1980 kernel/workqueue.c:3289
#1:
ffffc90000b67d08 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x973/0x1980 kernel/workqueue.c:3290
#2: ffff88802c26f1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline]
#2: ffff88802c26f1d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x1bd/0x4af0 drivers/usb/core/hub.c:5899
#3: ffff88802c26c568 (&port_dev->status_lock){+.+.}-{4:4}, at: usb_lock_port drivers/usb/core/hub.c:3252 [inline]
#3: ffff88802c26c568 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5464 [inline]
#3: ffff88802c26c568 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5707 [inline]
#3: ffff88802c26c568 (&port_dev->status_lock){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5871 [inline]
#3: ffff88802c26c568 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_event+0x2bd2/0x4af0 drivers/usb/core/hub.c:5953
#4: ffff8880217f3d60 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5465 [inline]
#4: ffff8880217f3d60 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5707 [inline]
#4: ffff8880217f3d60 (hcd->address0_mutex){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5871 [inline]
#4: ffff8880217f3d60 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_event+0x2bfb/0x4af0 drivers/usb/core/hub.c:5953
#5: ffffffff8fbc6788 (ehci_cf_port_reset_rwsem){.+.+}-{4:4}, at: hub_port_reset+0x1a5/0x1c60 drivers/usb/core/hub.c:3067
2 locks held by getty/5370:
#0: ffff888035bfe0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc900032332e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x14f0 drivers/tty/n_tty.c:2211
4 locks held by udevd/5602:
#0: ffff8880342acbd8 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xe1/0x1270 fs/seq_file.c:183
#1: ffff8880797a8480 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:172
#2: ffff88804e51a0f8 (kn->active#23){++++}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff88804e51a0f8 (kn->active#23){++++}-{0:0}, at: kernfs_seq_start+0xbc/0x2a0 fs/kernfs/file.c:173
#3: ffff8880226951d8 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:1045 [inline]
#3: ffff8880226951d8 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142
5 locks held by kworker/0:6/11071:
#0: ffff8880b843b2a0 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:660 [inline]
#0: ffff8880b843b2a0 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x88/0x140 kernel/sched/core.c:644
#1: ffff8880b8424648 (psi_seq){-.-.}-{0:0}, at: psi_sched_switch kernel/sched/stats.h:225 [inline]
#1: ffff8880b8424648 (psi_seq){-.-.}-{0:0}, at: __schedule+0x2f15/0x67a0 kernel/sched/core.c:7183
#2: ffffffff8eaa2af8 (kernfs_notify_lock){....}-{3:3}, at: spin_lock_irq include/linux/spinlock.h:372 [inline]
#2: ffffffff8eaa2af8 (kernfs_notify_lock){....}-{3:3}, at: kernfs_notify_workfn+0x7f/0x5f0 fs/kernfs/file.c:919
#3: ffff88801c6a7980 (&root->kernfs_rwsem){++++}-{4:4}, at: kernfs_notify_workfn+0xff/0x5f0 fs/kernfs/file.c:933
#4: ffffffff8e7e5620 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#4: ffffffff8e7e5620 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#4: ffffffff8e7e5620 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1181 [inline]
#4: ffffffff8e7e5620 (rcu_read_lock){....}-{1:3}, at: kernfs_root+0x23/0x2a0 fs/kernfs/kernfs-internal.h:74
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Call Trace:
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
nmi_cpu_backtrace.cold+0x12d/0x151 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x1d7/0x230 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+0x141/0x190 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
watchdog+0xcb1/0x1030 kernel/hung_task.c:561
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 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: 12553 Comm: syz.8.2029 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:__bfs+0x1c7/0x2a0 kernel/locking/lockdep.c:1815
Code: 81 e3 ff 0f 00 00 39 1d 67 c3 2d 14 48 89 04 f5 00 fc cc 96 73 11 89 1d 57 c3 2d 14 eb 09 0f 1f 44 00 00 4c 89 78 30 48 8b 00 <4c> 39 c0 75 f4 e9 22 ff ff ff b8 01 00 00 00 48 83 c4 30 5b 5d 41
RSP: 0018:ffffc9000691ecf8 EFLAGS: 00000002
RAX: ffffffff979f79d8 RBX: 00000000000000a5 RCX: 00000000000000c4
RDX: ffffffff96126ca8 RSI: 00000000000000c4 RDI: ffffffff97a00aa8
RBP: 0000000000000030 R08: ffffffff96126cd8 R09: 0000000000000020
R10: ffffc9000691ee88 R11: 0000000000000000 R12: ffffffff81e41b20
R13: ffffc9000691eda0 R14: ffffffff81e42930 R15: ffffffff97a00aa8
FS: 00007f9ef6acd6c0(0000) GS:ffff88812436d000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000002200 CR3: 000000005a4aa000 CR4: 00000000003526f0
Call Trace:
__bfs_backwards kernel/locking/lockdep.c:1860 [inline]
check_irq_usage+0xe5/0x810 kernel/locking/lockdep.c:2796
check_prev_add kernel/locking/lockdep.c:3169 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain kernel/locking/lockdep.c:3908 [inline]
__lock_acquire+0x14cf/0x2630 kernel/locking/lockdep.c:5237
lock_acquire kernel/locking/lockdep.c:5868 [inline]
lock_acquire+0x1b1/0x370 kernel/locking/lockdep.c:5825
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline]
_raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:166
uart_port_lock_irqsave include/linux/serial_core.h:717 [inline]
serial8250_console_write+0x17e/0x1900 drivers/tty/serial/8250/8250_port.c:3316
console_emit_next_record kernel/printk/printk.c:3183 [inline]
console_flush_one_record+0x790/0xe50 kernel/printk/printk.c:3269
console_flush_all kernel/printk/printk.c:3343 [inline]
__console_flush_and_unlock kernel/printk/printk.c:3373 [inline]
console_unlock+0x103/0x260 kernel/printk/printk.c:3413
vprintk_emit+0x407/0x6b0 kernel/printk/printk.c:2479
dev_vprintk_emit+0x394/0x3e0 drivers/base/core.c:4930
dev_printk_emit+0xd2/0x10d drivers/base/core.c:4941
__dev_printk+0xcb/0x100 drivers/base/core.c:4953
_dev_warn+0xef/0x127 drivers/base/core.c:4997
usb_submit_urb+0xe69/0x1910 drivers/usb/core/urb.c:508
snd_usb_endpoint_start+0x4c9/0xf40 sound/usb/endpoint.c:1624
start_endpoints+0xfb/0x1d0 sound/usb/pcm.c:291
snd_usb_substream_playback_trigger+0x6cb/0x890 sound/usb/pcm.c:1712
snd_pcm_do_start sound/core/pcm_native.c:1478 [inline]
snd_pcm_do_start+0xd4/0x1f0 sound/core/pcm_native.c:1471
snd_pcm_action_single+0x80/0x150 sound/core/pcm_native.c:1334
snd_pcm_action+0x70/0x90 sound/core/pcm_native.c:1417
__snd_pcm_lib_xfer+0x177b/0x20a0 sound/core/pcm_lib.c:2405
snd_pcm_oss_write3+0x8f/0x180 sound/core/oss/pcm_oss.c:1247
io_playback_transfer+0x26e/0x2f0 sound/core/oss/io.c:32
snd_pcm_plug_write_transfer+0x2c7/0x400 sound/core/oss/pcm_plugin.c:615
snd_pcm_oss_write2+0x24a/0x400 sound/core/oss/pcm_oss.c:1383
snd_pcm_oss_write1 sound/core/oss/pcm_oss.c:1449 [inline]
snd_pcm_oss_write+0x729/0xa30 sound/core/oss/pcm_oss.c:2811
vfs_write+0x2aa/0x1070 fs/read_write.c:686
ksys_write+0x12a/0x250 fs/read_write.c:740
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9ef5b9ce59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f9ef6acd028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f9ef5e15fa0 RCX: 00007f9ef5b9ce59
RDX: 00000000fffffcd9 RSI: 0000200000002200 RDI: 0000000000000007
RBP: 00007f9ef5c32d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9ef5e16038 R14: 00007f9ef5e15fa0 R15: 00007ffdcf77b528