INFO: task syz.1.1647:4688 blocked for more than 123 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.1647 state:D stack:0 pid:4688 tgid:4685 ppid:289 flags:0x00004002
Call Trace:
context_switch kernel/sched/core.c:5996 [inline]
__schedule+0x134f/0x1ea0 kernel/sched/core.c:7843
__schedule_loop kernel/sched/core.c:7924 [inline]
schedule+0xc5/0x240 kernel/sched/core.c:7939
schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:7996
__mutex_lock_common kernel/locking/mutex.c:707 [inline]
__mutex_lock+0x960/0x1bb0 kernel/locking/mutex.c:803
__mutex_lock_slowpath+0xe/0x20 kernel/locking/mutex.c:1134
mutex_lock+0x113/0x1d0 kernel/locking/mutex.c:285
rcu_barrier+0x4d/0x540 kernel/rcu/tree.c:4589
netdev_run_todo+0x118/0xce0 net/core/dev.c:10887
rtnl_unlock+0x12/0x20 net/core/rtnetlink.c:152
tun_detach drivers/net/tun.c:704 [inline]
tun_chr_close+0xc5/0x150 drivers/net/tun.c:3520
__fput+0x1fb/0xa00 fs/file_table.c:429
____fput+0x20/0x30 fs/file_table.c:457
task_work_run+0x1e5/0x260 kernel/task_work.c:246
exit_task_work include/linux/task_work.h:43 [inline]
do_exit+0x9e3/0x2650 kernel/exit.c:953
do_group_exit+0x229/0x2f0 kernel/exit.c:1095
get_signal+0x1398/0x14e0 kernel/signal.c:2933
arch_do_signal_or_restart+0xbc/0x760 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: 0033:0x7f1ac0b9c629
RSP: 002b:00007f1abf5d5fd8 EFLAGS: 00000202 ORIG_RAX: 0000000000000038
RAX: fffffffffffffff4 RBX: 00007f1ac0e16090 RCX: 00007f1ac0b9c629
RDX: 0000000000000000 RSI: 000000000000a420 RDI: 0000000000022080
RBP: 00007f1ac0c32b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 00007f1ac0e16128 R14: 00007f1ac0e16090 R15: 00007ffc1487f8e8
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 37924e2d96e0adc5b49b5912cddbdf0b22b3a5de
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
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: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+0xdad/0xf00 kernel/hung_task.c:423
kthread+0x2c9/0x370 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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 33 Comm: rcuop/1 Not tainted syzkaller #0 37924e2d96e0adc5b49b5912cddbdf0b22b3a5de
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:stack_trace_consume_entry+0xa6/0x2a0 kernel/stacktrace.c:93
Code: 41 0f b6 04 17 84 c0 0f 85 8d 01 00 00 45 89 34 24 b0 01 e9 a2 00 00 00 31 c0 e9 9b 00 00 00 48 89 f8 48 c1 e8 03 80 3c 10 00 <48> 89 75 c0 74 2b 49 89 ff 49 89 d4 4c 89 45 c8 4d 89 ce 4c 89 55
RSP: 0018:ffffc9000022fbd0 EFLAGS: 00000246
RAX: 1ffff92000045f9c RBX: 1ffff92000045f9e RCX: 000000000022fc00
RDX: dffffc0000000000 RSI: ffffffff847f03f5 RDI: ffffc9000022fce0
RBP: ffffc9000022fc18 R08: ffffc9000022fcf0 R09: ffffc9000022fce8
R10: 0000000000000010 R11: ffffffff8175cab0 R12: ffffc9000022fcec
R13: 1ffff92000045f9d R14: 0000000000000000 R15: 1ffff92000045f9d
FS: 0000000000000000(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0577616038 CR3: 0000000114d52000 CR4: 00000000003526b0
Call Trace:
arch_stack_walk+0x12c/0x170 arch/x86/kernel/stacktrace.c:27
stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:49 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:70
kasan_save_free_info+0x4a/0x60 mm/kasan/generic.c:579
poison_slab_object mm/kasan/common.c:249 [inline]
__kasan_slab_free+0x5f/0x80 mm/kasan/common.c:266
kasan_slab_free include/linux/kasan.h:234 [inline]
slab_free_hook mm/slub.c:2445 [inline]
slab_free mm/slub.c:4714 [inline]
kmem_cache_free+0x1bd/0x4f0 mm/slub.c:4821
kfree_skbmem net/core/skbuff.c:-1 [inline]
__kfree_skb+0x18f/0x210 net/core/skbuff.c:1203
sk_skb_reason_drop+0xd8/0x310 net/core/skbuff.c:1240
packet_rcv+0x180/0x1670 net/packet/af_packet.c:2276
dev_queue_xmit_nit+0xa3c/0xae0 net/core/dev.c:2425
xmit_one net/core/dev.c:3674 [inline]
dev_hard_start_xmit+0x187/0x760 net/core/dev.c:3697
__dev_queue_xmit+0x1905/0x3690 net/core/dev.c:4533
dev_queue_xmit include/linux/netdevice.h:3141 [inline]
br_dev_queue_push_xmit+0x55c/0x700 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+0x25c/0x390 net/bridge/br_forward.c:115
deliver_clone net/bridge/br_forward.c:131 [inline]
br_flood+0x67e/0x730 net/bridge/br_forward.c:246
br_handle_frame_finish+0x12f9/0x1760 net/bridge/br_input.c:215
nf_hook_bridge_pre net/bridge/br_input.c:301 [inline]
br_handle_frame+0x5a6/0xba0 net/bridge/br_input.c:424
__netif_receive_skb_core+0xfae/0x3ab0 net/core/dev.c:5670
__netif_receive_skb_one_core net/core/dev.c:5774 [inline]
__netif_receive_skb net/core/dev.c:5889 [inline]
process_backlog+0x3e5/0xad0 net/core/dev.c:6225
__napi_poll+0xd3/0x610 net/core/dev.c:6876
napi_poll net/core/dev.c:6945 [inline]
net_rx_action+0x5ea/0xd80 net/core/dev.c:7067
handle_softirqs+0x1aa/0x630 kernel/softirq.c:621
__do_softirq+0xf/0x16 kernel/softirq.c:659
do_softirq+0xb8/0x110 kernel/softirq.c:503
__local_bh_enable_ip+0x74/0x80 kernel/softirq.c:430
local_bh_enable include/linux/bottom_half.h:33 [inline]
rcu_do_batch+0x5d9/0xd40 kernel/rcu/tree.c:2594
nocb_cb_wait kernel/rcu/tree_nocb.h:923 [inline]
rcu_nocb_cb_kthread+0x524/0xb30 kernel/rcu/tree_nocb.h:957
kthread+0x2c9/0x370 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