INFO: task kworker/u8:16:23386 blocked for more than 144 seconds.
Tainted: G L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:16 state:D stack:21112 pid:23386 tgid:23386 ppid:2 task_flags:0x4208060 flags:0x00080000
Workqueue: events_unbound flush_to_ldisc
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5260 [inline]
__schedule+0x14ea/0x5050 kernel/sched/core.c:6867
__schedule_loop kernel/sched/core.c:6949 [inline]
schedule+0x164/0x360 kernel/sched/core.c:6964
schedule_timeout+0xc3/0x2c0 kernel/time/sleep_timeout.c:75
___down_common kernel/locking/semaphore.c:268 [inline]
__down_common+0x321/0x6a0 kernel/locking/semaphore.c:293
down+0x80/0xd0 kernel/locking/semaphore.c:100
console_lock+0x58/0x90 kernel/printk/printk.c:2843
class_console_lock_constructor include/linux/console.h:737 [inline]
con_flush_chars+0x6c/0x80 drivers/tty/vt/vt.c:3634
__receive_buf drivers/tty/n_tty.c:1620 [inline]
n_tty_receive_buf_common+0xca5/0x1300 drivers/tty/n_tty.c:1715
tty_port_default_receive_buf+0x6e/0xa0 drivers/tty/tty_port.c:37
receive_buf drivers/tty/tty_buffer.c:445 [inline]
flush_to_ldisc+0x24a/0x6e0 drivers/tty/tty_buffer.c:495
process_one_work kernel/workqueue.c:3257 [inline]
process_scheduled_works+0xaec/0x17a0 kernel/workqueue.c:3340
worker_thread+0xda6/0x1360 kernel/workqueue.c:3421
kthread+0x726/0x8b0 kernel/kthread.c:463
ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
</TASK>
Showing all locks held in the system:
1 lock held by kthreadd/2:
3 locks held by kworker/u8:1/13:
1 lock held by khungtaskd/31:
#0: ffffffff8e55a360 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e55a360 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8e55a360 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
3 locks held by kworker/u8:2/36:
3 locks held by kworker/u8:6/1114:
3 locks held by kworker/u8:8/1346:
5 locks held by kworker/R-krdsd/3398:
3 locks held by kworker/R-bat_e/3410:
1 lock held by klogd/5184:
2 locks held by udevd/5195:
2 locks held by dhcpcd/5489:
1 lock held by dhcpcd/5490:
2 locks held by getty/5582:
#0: ffff888030cdd0a0 (&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+0x45c/0x13c0 drivers/tty/n_tty.c:2211
3 locks held by kworker/u8:3/15103:
4 locks held by kworker/1:1/18009:
5 locks held by syz-executor/19879:
2 locks held by kworker/1:2/20306:
3 locks held by kworker/u8:12/23224:
4 locks held by kworker/u8:15/23384:
5 locks held by kworker/u8:16/23386:
#0: ffff88813fe69948 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline]
#0: ffff88813fe69948 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_scheduled_works+0x9d4/0x17a0 kernel/workqueue.c:3340
#1: ffffc90003f9fbc0 ((work_completion)(&buf->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline]
#1: ffffc90003f9fbc0 ((work_completion)(&buf->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa0f/0x17a0 kernel/workqueue.c:3340
#2: ffff88813fec10b8 (&buf->lock){+.+.}-{4:4}, at: flush_to_ldisc+0x38/0x6e0 drivers/tty/tty_buffer.c:467
#3: ffff88807a9140a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref+0x1c/0x90 drivers/tty/tty_ldisc.c:263
#4: ffff88807a9142e8 (&tty->termios_rwsem){++++}-{4:4}, at: class_rwsem_read_constructor include/linux/rwsem.h:253 [inline]
#4: ffff88807a9142e8 (&tty->termios_rwsem){++++}-{4:4}, at: n_tty_receive_buf_common+0x84/0x1300 drivers/tty/n_tty.c:1678
3 locks held by kworker/u8:18/23389:
3 locks held by kworker/0:0/25481:
1 lock held by syz-executor/28021:
2 locks held by syz-executor/28449:
2 locks held by syz.1.6351/29337:
1 lock held by syz.1.6849/31312:
6 locks held by syz.5.6853/31323:
3 locks held by v4l_id/31327:
3 locks held by kworker/u8:0/31328:
3 locks held by kworker/u8:4/31329:
3 locks held by kworker/u8:5/31330:
3 locks held by kworker/u8:7/31331:
3 locks held by kworker/u8:9/31332:
3 locks held by syz-executor/31334:
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/13/2026
Call Trace:
<TASK>
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+0xf90/0xfe0 kernel/hung_task.c:515
kthread+0x726/0x8b0 kernel/kthread.c:463
ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
</TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 3410 Comm: kworker/R-bat_e Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/13/2026
Workqueue: bat_events batadv_dat_purge
RIP: 0010:arch_stack_walk+0x122/0x150 arch/x86/kernel/stacktrace.c:24
Code: 6d 09 00 48 85 c0 74 24 48 89 df 48 89 c6 4d 89 f3 2e e8 99 15 94 1e 84 c0 74 11 4c 89 ff e8 95 6e 09 00 83 bd 78 ff ff ff 00 <75> cf 65 48 8b 05 b4 8d 86 11 48 3b 45 d8 75 12 48 83 c4 68 5b 41
RSP: 0018:ffffc90000a07708 EFLAGS: 00000202
RAX: 0000000091154401 RBX: ffffc90000a077c0 RCX: 0000000080000101
RDX: 0000000000000005 RSI: ffffffff8df34258 RDI: ffff8880313f1e80
RBP: ffffc90000a07790 R08: ffffc90000a07f10 R09: 0000000000000000
R10: ffffc90000a07758 R11: fffff52000140eed R12: ffff8880313f1e80
R13: 0000000000000000 R14: ffffffff81afb170 R15: ffffc90000a07708
FS: 0000000000000000(0000) GS:ffff8881257f5000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000003fa030 CR3: 00000000287d4000 CR4: 00000000003526f0
Call Trace:
<IRQ>
stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:253 [inline]
__kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
kasan_slab_free include/linux/kasan.h:235 [inline]
slab_free_hook mm/slub.c:2540 [inline]
slab_free mm/slub.c:6674 [inline]
kmem_cache_free+0x195/0x610 mm/slub.c:6785
skb_ext_del include/linux/skbuff.h:5057 [inline]
nf_bridge_info_free net/bridge/br_netfilter_hooks.c:156 [inline]
br_nf_dev_queue_xmit+0x4ef/0x2560 net/bridge/br_netfilter_hooks.c:851
NF_HOOK+0x64e/0x6e0 include/linux/netfilter.h:318
br_nf_post_routing+0xb66/0xfe0 net/bridge/br_netfilter_hooks.c:966
nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
nf_hook_slow+0xc5/0x220 net/netfilter/core.c:623
nf_hook include/linux/netfilter.h:273 [inline]
NF_HOOK+0x23e/0x3f0 include/linux/netfilter.h:316
br_forward_finish+0xd3/0x130 net/bridge/br_forward.c:66
br_nf_hook_thresh net/bridge/br_netfilter_hooks.c:1167 [inline]
br_nf_forward_finish+0xa5e/0xe90 net/bridge/br_netfilter_hooks.c:662
NF_HOOK+0x64e/0x6e0 include/linux/netfilter.h:318
br_nf_forward_ip+0x7ef/0xa30 net/bridge/br_netfilter_hooks.c:716
nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
nf_hook_slow+0xc5/0x220 net/netfilter/core.c:623
nf_hook include/linux/netfilter.h:273 [inline]
NF_HOOK+0x23e/0x3f0 include/linux/netfilter.h:316
__br_forward+0x397/0x540 net/bridge/br_forward.c:115
br_handle_frame_finish+0x1436/0x1b40 net/bridge/br_input.c:231
br_nf_hook_thresh+0x3dd/0x4c0 net/bridge/br_netfilter_hooks.c:-1
br_nf_pre_routing_finish_ipv6+0xa3a/0xd70 net/bridge/br_netfilter_ipv6.c:-1
NF_HOOK include/linux/netfilter.h:318 [inline]
br_nf_pre_routing_ipv6+0x374/0x6f0 net/bridge/br_netfilter_ipv6.c:184
nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
nf_hook_bridge_pre net/bridge/br_input.c:291 [inline]
br_handle_frame+0x989/0x1520 net/bridge/br_input.c:442
__netif_receive_skb_core+0x98f/0x30a0 net/core/dev.c:6039
__netif_receive_skb_one_core net/core/dev.c:6150 [inline]
__netif_receive_skb net/core/dev.c:6265 [inline]
process_backlog+0x76d/0x1950 net/core/dev.c:6617
__napi_poll+0xae/0x340 net/core/dev.c:7681
napi_poll net/core/dev.c:7744 [inline]
net_rx_action+0x627/0xf70 net/core/dev.c:7896
handle_softirqs+0x22a/0x7c0 kernel/softirq.c:622
do_softirq+0x76/0xd0 kernel/softirq.c:523
</IRQ>
<TASK>
__local_bh_enable_ip+0xf8/0x130 kernel/softirq.c:450
spin_unlock_bh include/linux/spinlock.h:396 [inline]
__batadv_dat_purge net/batman-adv/distributed-arp-table.c:185 [inline]
batadv_dat_purge+0x2da/0x3c0 net/batman-adv/distributed-arp-table.c:204
process_one_work kernel/workqueue.c:3257 [inline]
process_scheduled_works+0xaec/0x17a0 kernel/workqueue.c:3340
rescuer_thread+0xcba/0x1390 kernel/workqueue.c:3528
kthread+0x726/0x8b0 kernel/kthread.c:463
ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
</TASK>