INFO: task kworker/1:6:550 blocked for more than 122 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:6 state:D stack:0 pid:550 tgid:550 ppid:2 flags:0x00004000
Workqueue: events fqdir_free_fn
Call Trace:
<TASK>
context_switch kernel/sched/core.c:6027 [inline]
__schedule+0x14ce/0x2100 kernel/sched/core.c:7894
__schedule_loop kernel/sched/core.c:7975 [inline]
schedule+0xc5/0x240 kernel/sched/core.c:7990
schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:8047
__mutex_lock_common kernel/locking/mutex.c:707 [inline]
__mutex_lock+0x960/0x1bc0 kernel/locking/mutex.c:805
__mutex_lock_slowpath+0xe/0x20 kernel/locking/mutex.c:1136
mutex_lock+0x113/0x1d0 kernel/locking/mutex.c:285
rcu_barrier+0x4d/0x540 kernel/rcu/tree.c:4589
fqdir_free_fn+0x36/0x150 net/ipv4/inet_fragment.c:167
process_one_work kernel/workqueue.c:3261 [inline]
process_scheduled_works+0x7d4/0x1020 kernel/workqueue.c:3342
worker_thread+0xc51/0x1370 kernel/workqueue.c:3423
kthread+0x2c9/0x370 kernel/kthread.c:389
ret_from_fork+0x67/0xa0 arch/x86/kernel/process.c:153
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 471281939cd7bfdfff4c6b6074d5d68627c837ba
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
<TASK>
__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+0x67/0xa0 arch/x86/kernel/process.c:153
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>
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 471281939cd7bfdfff4c6b6074d5d68627c837ba
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:update_stack_state+0x8/0x4b0 arch/x86/kernel/unwind_frame.c:198
Code: 90 90 55 48 89 e5 48 8b 07 5d e9 c3 27 66 04 cc 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 48 89 e5 41 57 41 56 <41> 55 41 54 53 48 81 ec 98 00 00 00 49 89 f7 48 89 fb 49 bd 00 00
RSP: 0018:ffffc90000007168 EFLAGS: 00000246
RAX: ffffc90000007d30 RBX: ffffc90000007208 RCX: 0000000000007200
RDX: dffffc0000000000 RSI: ffffc90000007d30 RDI: ffffc90000007208
RBP: ffffc90000007178 R08: ffffc900000072d0 R09: ffffc900000072c8
R10: 000000000000000a R11: ffffffff8175ee80 R12: 0000000000000000
R13: 1ffff92000000e4c R14: ffffc90000007260 R15: ffffc90000007ce0
FS: 0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa7aca0a368 CR3: 00000000074aa000 CR4: 00000000003526b0
Call Trace:
<IRQ>
unwind_next_frame+0x3c1/0x750 arch/x86/kernel/unwind_frame.c:315
arch_stack_walk+0x138/0x170 arch/x86/kernel/stacktrace.c:25
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_alloc_info+0x40/0x50 mm/kasan/generic.c:565
unpoison_slab_object mm/kasan/common.c:321 [inline]
__kasan_slab_alloc+0x73/0x90 mm/kasan/common.c:347
kasan_slab_alloc include/linux/kasan.h:251 [inline]
slab_post_alloc_hook mm/slub.c:4202 [inline]
slab_alloc_node mm/slub.c:4251 [inline]
kmem_cache_alloc_noprof+0x1bf/0x410 mm/slub.c:4260
skb_clone+0x229/0x460 net/core/skbuff.c:2082
deliver_clone net/bridge/br_forward.c:125 [inline]
maybe_deliver net/bridge/br_forward.c:191 [inline]
br_flood+0x4ed/0x730 net/bridge/br_forward.c:237
br_handle_frame_finish+0x11eb/0x17a0 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:5695
__netif_receive_skb_one_core net/core/dev.c:5799 [inline]
__netif_receive_skb net/core/dev.c:5914 [inline]
process_backlog+0x3e5/0xad0 net/core/dev.c:6250
__napi_poll+0xd0/0x610 net/core/dev.c:6901
napi_poll net/core/dev.c:6970 [inline]
net_rx_action+0x5ea/0xd80 net/core/dev.c:7092
handle_softirqs+0x1aa/0x630 kernel/softirq.c:621
__do_softirq+0xf/0x16 kernel/softirq.c:659
do_softirq+0xb8/0x110 kernel/softirq.c:503
</IRQ>
<TASK>
__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+0x67/0xa0 arch/x86/kernel/process.c:153
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>
net_ratelimit: 110672 callbacks suppressed
bridge0: received packet on veth0_to_bridge with own address as source address (addr:a6:9e:8c:a9:ac:29, 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 bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, 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:a6:9e:8c:a9:ac:29, 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)
net_ratelimit: 119770 callbacks suppressed
bridge0: received packet on veth0_to_bridge with own address as source address (addr:a6:9e:8c:a9:ac:29, 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 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 veth0_to_bridge with own address as source address (addr:a6:9e:8c:a9:ac:29, 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)