INFO: task kworker/u8:5:461 blocked for more than 123 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:5 state:D stack:0 pid:461 tgid:461 ppid:2 flags:0x00004000
Workqueue: events_unbound linkwatch_event
Call Trace:
context_switch kernel/sched/core.c:6124 [inline]
__schedule+0x16e0/0x2380 kernel/sched/core.c:7971
__schedule_loop kernel/sched/core.c:8046 [inline]
schedule+0xc1/0x170 kernel/sched/core.c:8061
schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:8118
__mutex_lock_common kernel/locking/mutex.c:707 [inline]
__mutex_lock+0x95d/0x1d10 kernel/locking/mutex.c:807
__mutex_lock_slowpath+0xe/0x20 kernel/locking/mutex.c:1137
mutex_lock+0x113/0x1d0 kernel/locking/mutex.c:285
rtnl_lock+0x19/0x20 net/core/rtnetlink.c:79
linkwatch_event+0x12/0x60 net/core/link_watch.c:285
process_one_work kernel/workqueue.c:3273 [inline]
process_scheduled_works+0x7f7/0x1060 kernel/workqueue.c:3354
worker_thread+0xc99/0x13f0 kernel/workqueue.c:3435
kthread+0x2c7/0x360 kernel/kthread.c:389
ret_from_fork+0x64/0xa0 arch/x86/kernel/process.c:153
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
INFO: task syz.2.408:1736 blocked for more than 124 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.408 state:D stack:0 pid:1736 tgid:1736 ppid:296 flags:0x00004006
Call Trace:
context_switch kernel/sched/core.c:6124 [inline]
__schedule+0x16e0/0x2380 kernel/sched/core.c:7971
__schedule_loop kernel/sched/core.c:8046 [inline]
schedule+0xc1/0x170 kernel/sched/core.c:8061
schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:8118
__mutex_lock_common kernel/locking/mutex.c:707 [inline]
__mutex_lock+0x95d/0x1d10 kernel/locking/mutex.c:807
__mutex_lock_slowpath+0xe/0x20 kernel/locking/mutex.c:1137
mutex_lock+0x113/0x1d0 kernel/locking/mutex.c:285
rtnl_lock+0x19/0x20 net/core/rtnetlink.c:79
tun_detach drivers/net/tun.c:698 [inline]
tun_chr_close+0x41/0x150 drivers/net/tun.c:3523
__fput+0x208/0xa30 fs/file_table.c:447
____fput+0x20/0x30 fs/file_table.c:475
task_work_run+0x1e8/0x260 kernel/task_work.c:246
exit_task_work include/linux/task_work.h:43 [inline]
do_exit+0xa46/0x2850 kernel/exit.c:961
do_group_exit+0x21f/0x2f0 kernel/exit.c:1104
get_signal+0x134c/0x1490 kernel/signal.c:2942
arch_do_signal_or_restart+0xbc/0x700 arch/x86/kernel/signal.c:337
exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
__syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
syscall_exit_to_user_mode+0x57/0xb0 kernel/entry/common.c:218
do_syscall_64+0x63/0xf0 arch/x86/entry/common.c:84
entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f9c5b96034e
RSP: 002b:00007f9c5c91ff58 EFLAGS: 00000246 ORIG_RAX: 00000000000000e6
RAX: fffffffffffffdfc RBX: 00007f9c5c9206c0 RCX: 00007f9c5b96034e
RDX: 00007f9c5c91ffb0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f9c5ba37b70 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9c5bc26038 R14: 00007f9c5bc25fa0 R15: 00007ffe946360e8
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 ff996278633adec6fd25d1632b496761701c4fe9
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/06/2026
Call Trace:
__dump_stack+0x21/0x30 lib/dump_stack.c:94
dump_stack_lvl+0x140/0x1c0 lib/dump_stack.c:120
dump_stack+0x19/0x20 lib/dump_stack.c:129
nmi_cpu_backtrace+0x2ba/0x2d0 lib/nmi_backtrace.c:114
nmi_trigger_cpumask_backtrace+0x142/0x2c0 lib/nmi_backtrace.c:63
arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:41
cpumask_backtrace+0x1f/0x30 lib/nmi_backtrace.c:127
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:267 [inline]
watchdog+0xe45/0xf90 kernel/hung_task.c:423
kthread+0x2c7/0x360 kernel/kthread.c:389
ret_from_fork+0x64/0xa0 arch/x86/kernel/process.c:153
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 20 Comm: rcuop/0 Not tainted syzkaller #0 ff996278633adec6fd25d1632b496761701c4fe9
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/06/2026
RIP: 0010:veth_forward_skb drivers/net/veth.c:322 [inline]
RIP: 0010:veth_xmit+0x33b/0xb30 drivers/net/veth.c:378
Code: 4c 89 ff 4c 89 f6 e8 f4 4f 0c 01 41 89 c7 31 ff 89 c6 e8 48 26 0f fe 45 85 ff 74 0a e8 fe 21 0f fe e9 a6 01 00 00 80 7d c0 00 <0f> 84 d2 00 00 00 49 8d bd 44 02 00 00 48 89 7d b0 e8 1f ab 32 02
RSP: 0018:ffffc90000007130 EFLAGS: 00000246
RAX: ffffffff837a47c8 RBX: 0000000000000000 RCX: 0000000000000100
RDX: ffff8881036662c0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900000071b8 R08: ffff8881036662c0 R09: 0000000000000002
R10: 0000000000000003 R11: 0000000000000100 R12: dffffc0000000000
R13: ffff888106772000 R14: ffff88815f2cda00 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8881f6c00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055ffc1d38af8 CR3: 0000000007caa000 CR4: 00000000003526b0
Call Trace:
__netdev_start_xmit include/linux/netdevice.h:5008 [inline]
netdev_start_xmit include/linux/netdevice.h:5017 [inline]
xmit_one net/core/dev.c:3693 [inline]
dev_hard_start_xmit+0x230/0x730 net/core/dev.c:3709
__dev_queue_xmit+0x1969/0x3780 net/core/dev.c:4549
dev_queue_xmit include/linux/netdevice.h:3141 [inline]
br_dev_queue_push_xmit+0x571/0x710 net/bridge/br_forward.c:53
NF_HOOK include/linux/netfilter.h:317 [inline]
br_forward_finish net/bridge/br_forward.c:66 [inline]
NF_HOOK include/linux/netfilter.h:317 [inline]
__br_forward+0x24f/0x390 net/bridge/br_forward.c:115
deliver_clone net/bridge/br_forward.c:131 [inline]
maybe_deliver net/bridge/br_forward.c:191 [inline]
br_flood+0x500/0x720 net/bridge/br_forward.c:237
br_handle_frame_finish+0x1157/0x1620 net/bridge/br_input.c:215
nf_hook_bridge_pre net/bridge/br_input.c:301 [inline]
br_handle_frame+0x5a5/0xba0 net/bridge/br_input.c:424
__netif_receive_skb_core+0xfc4/0x3a70 net/core/dev.c:5695
__netif_receive_skb_one_core net/core/dev.c:5799 [inline]
__netif_receive_skb net/core/dev.c:5914 [inline]
process_backlog+0x40b/0xaf0 net/core/dev.c:6250
__napi_poll+0xcd/0x600 net/core/dev.c:6901
napi_poll net/core/dev.c:6970 [inline]
net_rx_action+0x5dc/0xd70 net/core/dev.c:7092
handle_softirqs+0x1b0/0x5b0 kernel/softirq.c:684
__do_softirq+0xf/0x16 kernel/softirq.c:722
do_softirq+0xb8/0x110 kernel/softirq.c:566
__local_bh_enable_ip+0x74/0x80 kernel/softirq.c:493
local_bh_enable include/linux/bottom_half.h:33 [inline]
rcu_do_batch+0x590/0xcb0 kernel/rcu/tree.c:2594
nocb_cb_wait kernel/rcu/tree_nocb.h:923 [inline]
rcu_nocb_cb_kthread+0x533/0xb60 kernel/rcu/tree_nocb.h:957
kthread+0x2c7/0x360 kernel/kthread.c:389
ret_from_fork+0x64/0xa0 arch/x86/kernel/process.c:153
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
net_ratelimit: 139426 callbacks suppressed
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:6e:6a:69:ac:9e:1f, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:6e:6a:69:ac:9e:1f, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)