INFO: task kworker/u8:4:329 blocked for more than 122 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:4 state:D stack:0 pid:329 tgid:329 ppid:2 flags:0x00004000
Workqueue: netns cleanup_net
Call Trace:
context_switch kernel/sched/core.c:5945 [inline]
__schedule+0x1322/0x1df0 kernel/sched/core.c:7791
__schedule_loop kernel/sched/core.c:7872 [inline]
schedule+0xc6/0x240 kernel/sched/core.c:7887
schedule_timeout+0xb2/0x3a0 kernel/time/timer.c:2595
do_wait_for_common kernel/sched/completion.c:95 [inline]
__wait_for_common kernel/sched/completion.c:116 [inline]
wait_for_common+0x359/0x630 kernel/sched/completion.c:127
wait_for_completion+0x1c/0x40 kernel/sched/completion.c:148
rcu_barrier+0x415/0x530 kernel/rcu/tree.c:4657
netdev_run_todo+0x10e/0xcb0 net/core/dev.c:10868
rtnl_unlock+0x12/0x20 net/core/rtnetlink.c:152
default_device_exit_batch+0x815/0x8a0 net/core/dev.c:12035
ops_exit_list net/core/net_namespace.c:178 [inline]
cleanup_net+0x731/0xc70 net/core/net_namespace.c:642
process_one_work kernel/workqueue.c:3238 [inline]
process_scheduled_works+0x7d5/0x1020 kernel/workqueue.c:3319
worker_thread+0xc58/0x1250 kernel/workqueue.c:3400
kthread+0x2c7/0x370 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
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 0dd0103ec329b4c3ce546fdd10bdf8515cdb9785
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/14/2025
Call Trace:
__dump_stack+0x21/0x30 lib/dump_stack.c:94
dump_stack_lvl+0x10c/0x190 lib/dump_stack.c:120
dump_stack+0x19/0x20 lib/dump_stack.c:129
nmi_cpu_backtrace+0x2bf/0x2d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x142/0x2c0 lib/nmi_backtrace.c:62
arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:41
trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:267 [inline]
watchdog+0xd8f/0xed0 kernel/hung_task.c:423
kthread+0x2c7/0x370 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: 6287 Comm: syz-executor Not tainted syzkaller #0 0dd0103ec329b4c3ce546fdd10bdf8515cdb9785
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/14/2025
RIP: 0010:on_stack arch/x86/include/asm/stacktrace.h:-1 [inline]
RIP: 0010:update_stack_state+0x1bb/0x4b0 arch/x86/kernel/unwind_frame.c:228
Code: ff ff 42 80 3c 28 00 74 0c 48 8b bd 70 ff ff ff e8 5a e4 97 00 4c 8b 73 10 48 8b 45 b8 42 0f b6 04 28 84 c0 0f 85 8c 00 00 00 <49> 89 dc 44 8b 2b 45 85 ed 0f 95 c0 48 8b 55 b0 4c 39 fa 0f 93 c1
RSP: 0018:ffffc9000d50f2d8 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffffc9000d50f428 RCX: 1ffff92001aa1e87
RDX: 1ffff92001aa1e88 RSI: 1ffff92001aa1e86 RDI: ffffc9000d50f480
RBP: ffffc9000d50f398 R08: ffffc9000d50f4f0 R09: ffffc9000d50f4e8
R10: 000000000000000a R11: ffffffff817441e0 R12: 0000000000000000
R13: dffffc0000000000 R14: ffffc9000d510000 R15: ffffc9000d508000
FS: 0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8e48cf7d60 CR3: 000000012056e000 CR4: 00000000003526b0
DR0: 0000000000000000 DR1: 000000000000000e DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
unwind_next_frame+0x3c2/0x750 arch/x86/kernel/unwind_frame.c:315
arch_stack_walk+0x139/0x170 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x9d/0xe0 kernel/stacktrace.c:122
save_stack+0xf8/0x1f0 mm/page_owner.c:174
__reset_page_owner+0x79/0x450 mm/page_owner.c:315
reset_page_owner include/linux/page_owner.h:28 [inline]
free_pages_prepare mm/page_alloc.c:1352 [inline]
free_unref_page+0xb4d/0xee0 mm/page_alloc.c:2842
__free_pages+0x6b/0x3b0 mm/page_alloc.c:5345
vfree+0x3bf/0x580 mm/vmalloc.c:3396
kcov_put kernel/kcov.c:439 [inline]
kcov_close+0x2c/0x70 kernel/kcov.c:535
__fput+0x1fe/0xa00 fs/file_table.c:429
____fput+0x20/0x30 fs/file_table.c:457
task_work_run+0x1e3/0x250 kernel/task_work.c:240
exit_task_work include/linux/task_work.h:43 [inline]
do_exit+0x9bc/0x2630 kernel/exit.c:953
do_group_exit+0x22a/0x300 kernel/exit.c:1095
get_signal+0x139d/0x14f0 kernel/signal.c:2933
arch_do_signal_or_restart+0x96/0x720 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+0x58/0xb0 kernel/entry/common.c:218
do_syscall_64+0x64/0xf0 arch/x86/entry/common.c:89
entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f43de190a23
Code: Unable to access opcode bytes at 0x7f43de1909f9.
RSP: 002b:00007ffcbee11c38 EFLAGS: 00000202 ORIG_RAX: 000000000000002c
RAX: 0000000000000028 RBX: 00007f43deef4620 RCX: 00007f43de190a23
RDX: 0000000000000028 RSI: 00007f43deef4670 RDI: 0000000000000003
RBP: 0000000000000001 R08: 00007ffcbee11c54 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000003
R13: 0000000000000000 R14: 00007f43deef4670 R15: 0000000000000000
net_ratelimit: 107169 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 bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, 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:f2:41:80:bc:83:09, 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:1b, 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:f2:41:80:bc:83:09, 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:f2:41:80:bc:83:09, vlan:0)