INFO: task syz.7.7793:20141 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.7.7793 state:D stack:28200 pid:20141 tgid:20103 ppid:31682 task_flags:0x400040 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6961
__schedule_loop kernel/sched/core.c:7043 [inline]
schedule+0x165/0x360 kernel/sched/core.c:7058
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7115
__mutex_lock_common kernel/locking/mutex.c:676 [inline]
__mutex_lock+0x7e6/0x1350 kernel/locking/mutex.c:760
snd_seq_info_clients_read+0x14a/0x7e0 sound/core/seq/seq_clientmgr.c:2743
snd_info_seq_show+0xd6/0x100 sound/core/info.c:342
traverse+0x1e6/0x570 fs/seq_file.c:111
seq_read_iter+0xcfe/0xe10 fs/seq_file.c:195
seq_read+0x369/0x480 fs/seq_file.c:162
pde_read fs/proc/inode.c:308 [inline]
proc_reg_read+0x1e9/0x2e0 fs/proc/inode.c:320
do_loop_readv_writev fs/read_write.c:847 [inline]
vfs_readv+0x5a7/0x850 fs/read_write.c:1020
do_preadv fs/read_write.c:1132 [inline]
__do_sys_preadv fs/read_write.c:1179 [inline]
__se_sys_preadv fs/read_write.c:1174 [inline]
__x64_sys_preadv+0x197/0x2a0 fs/read_write.c:1174
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fec6458eba9
RSP: 002b:00007fec612d2038 EFLAGS: 00000246 ORIG_RAX: 0000000000000127
RAX: ffffffffffffffda RBX: 00007fec647d6630 RCX: 00007fec6458eba9
RDX: 0000000000000001 RSI: 0000200000004ec0 RDI: 0000000000000009
RBP: 00007fec64611e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000008000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fec647d66c8 R14: 00007fec647d6630 R15: 00007fec648ffa28
Showing all locks held in the system:
3 locks held by kauditd/30:
1 lock held by khungtaskd/31:
#0: ffffffff8e13a0e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e13a0e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#0: ffffffff8e13a0e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by getty/5627:
#0: ffff88814ceef0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
5 locks held by kworker/1:6/5958:
#0: ffff888022684948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline]
#0: ffff888022684948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319
#1: ffffc90005277bc0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline]
#1: ffffc90005277bc0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319
#2: ffff888028298198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:911 [inline]
#2: ffff888028298198 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4a20 drivers/usb/core/hub.c:5898
#3: ffff88802829b518 (&port_dev->status_lock){+.+.}-{4:4}, at: usb_lock_port drivers/usb/core/hub.c:3251 [inline]
#3: ffff88802829b518 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5463 [inline]
#3: ffff88802829b518 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5706 [inline]
#3: ffff88802829b518 (&port_dev->status_lock){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5870 [inline]
#3: ffff88802829b518 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_event+0x21b8/0x4a20 drivers/usb/core/hub.c:5952
#4: ffff88814470cc68 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5464 [inline]
#4: ffff88814470cc68 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5706 [inline]
#4: ffff88814470cc68 (hcd->address0_mutex){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5870 [inline]
#4: ffff88814470cc68 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_event+0x21e5/0x4a20 drivers/usb/core/hub.c:5952
1 lock held by syz.2.2418/14987:
#0: ffff8880246469d0 (&client->ioctl_mutex){+.+.}-{4:4}, at: snd_seq_ioctl+0x232/0x420 sound/core/seq/seq_clientmgr.c:2384
2 locks held by syz.7.7793/20141:
#0: ffff888035047c30 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xb7/0xe10 fs/seq_file.c:182
#1: ffff8880246469d0 (&client->ioctl_mutex){+.+.}-{4:4}, at: snd_seq_info_clients_read+0x14a/0x7e0 sound/core/seq/seq_clientmgr.c:2743
3 locks held by kworker/u8:5/21445:
1 lock held by syz.3.8338/25152:
1 lock held by syz.2.8340/25164:
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
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:328 [inline]
watchdog+0xf93/0xfe0 kernel/hung_task.c:491
kthread+0x70e/0x8a0 kernel/kthread.c:463
ret_from_fork+0x436/0x7d0 arch/x86/kernel/process.c:148
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: 24495 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:accumulate_sum kernel/sched/pelt.c:116 [inline]
RIP: 0010:___update_load_sum kernel/sched/pelt.c:227 [inline]
RIP: 0010:__update_load_avg_cfs_rq+0x1bf/0xbd0 kernel/sched/pelt.c:323
Code: 85 99 02 00 00 e9 3e 03 00 00 41 80 3c 37 00 74 08 4c 89 ef e8 d2 0f 8c 00 4d 89 75 00 45 31 f6 e9 4d 05 00 00 48 89 44 24 30 <4d> 8d b4 24 88 00 00 00 4d 89 f7 49 c1 ef 03 41 80 3c 37 00 74 1c
RSP: 0018:ffffc9000dff76e8 EFLAGS: 00000002
RAX: 00000000000003a1 RBX: ffff8880b873a0dc RCX: 4ca7598cf16c1e00
RDX: 00000000000000c1 RSI: dffffc0000000000 RDI: 0000000000000462
RBP: 0000000000001400 R08: ffffffff8fa3a537 R09: 1ffffffff1f474a6
R10: dffffc0000000000 R11: fffffbfff1f474a7 R12: ffff8880b873a040
R13: 0000000000000005 R14: 0000021acae18800 R15: 1ffff110170e7418
FS: 000055557bb8e500(0000) GS:ffff888125d15000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000404030 CR3: 0000000028ca0000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 00000000ffff000b DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
update_cfs_rq_load_avg kernel/sched/fair.c:4618 [inline]
update_load_avg+0x572/0x1880 kernel/sched/fair.c:4731
dequeue_entity+0x3f9/0x1690 kernel/sched/fair.c:5420
dequeue_entities+0x1c0/0x13d0 kernel/sched/fair.c:6984
dequeue_task_fair+0x205/0x580 kernel/sched/fair.c:7080
block_task kernel/sched/core.c:2155 [inline]
try_to_block_task kernel/sched/core.c:6585 [inline]
__schedule+0x5f1/0x4cc0 kernel/sched/core.c:6896
__schedule_loop kernel/sched/core.c:7043 [inline]
schedule+0x165/0x360 kernel/sched/core.c:7058
do_nanosleep+0x1c7/0x600 kernel/time/hrtimer.c:2100
hrtimer_nanosleep+0x169/0x360 kernel/time/hrtimer.c:2147
__do_sys_clock_nanosleep kernel/time/posix-timers.c:1399 [inline]
__se_sys_clock_nanosleep+0x2f1/0x380 kernel/time/posix-timers.c:1376
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f798dbc1465
Code: 24 0c 89 3c 24 48 89 4c 24 18 e8 f6 54 ff ff 4c 8b 54 24 18 48 8b 54 24 10 41 89 c0 8b 74 24 0c 8b 3c 24 b8 e6 00 00 00 0f 05 <44> 89 c7 48 89 04 24 e8 4f 55 ff ff 48 8b 04 24 48 83 c4 28 f7 d8
RSP: 002b:00007f798deffd40 EFLAGS: 00000293 ORIG_RAX: 00000000000000e6
RAX: ffffffffffffffda RBX: 0000000000000011 RCX: 00007f798dbc1465
RDX: 00007f798deffd80 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f798deffdec R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000001388
R13: 00000000000927c0 R14: 00000000002510dd R15: 00007f798deffe40