INFO: task kworker/0:4:758 blocked for more than 122 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:4 state:D stack:0 pid:758 tgid:758 ppid:2 flags:0x00004000
Workqueue: events fqdir_free_fn
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_preempt_disabled+0x14/0x30 kernel/sched/core.c:7944
__mutex_lock_common kernel/locking/mutex.c:707 [inline]
__mutex_lock+0x81e/0x1b50 kernel/locking/mutex.c:803
__mutex_lock_slowpath+0xe/0x20 kernel/locking/mutex.c:1134
mutex_lock+0x102/0x1c0 kernel/locking/mutex.c:285
rcu_barrier+0x4d/0x530 kernel/rcu/tree.c:4589
fqdir_free_fn+0x36/0x150 net/ipv4/inet_fragment.c:167
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
INFO: task syz.2.948:3304 blocked for more than 124 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.948 state:D stack:0 pid:3304 tgid:3304 ppid:290 flags:0x00004006
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
ppp_release+0xf5/0x200 drivers/net/ppp/ppp_generic.c:422
__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: 0033:0x7f06549c14a5
RSP: 002b:00007f0655824f80 EFLAGS: 00000293 ORIG_RAX: 00000000000000e6
RAX: fffffffffffffdfc RBX: 00007f0654bc5fa0 RCX: 00007f06549c14a5
RDX: 00007f0655824fc0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f0654a11e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000
R13: 00007f0654bc6038 R14: 00007f0654bc5fa0 R15: 00007ffcbad15c98
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 0dd0103ec329b4c3ce546fdd10bdf8515cdb9785
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 20 Comm: rcuop/0 Not tainted syzkaller #0 0dd0103ec329b4c3ce546fdd10bdf8515cdb9785
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:unwind_next_frame+0x383/0x750 arch/x86/kernel/unwind_frame.c:311
Code: e0 48 c1 e8 03 80 3c 10 00 4c 8b 75 d0 4c 8b 6d c0 74 08 4c 89 e7 e8 fc e9 97 00 49 8b 04 24 eb 39 65 48 8b 04 25 00 eb 04 00 <48> 39 45 a8 4c 8b 75 d0 4c 8b 6d c0 74 0a 4c 89 ff e8 b7 03 00 00
RSP: 0018:ffffc9000022ffc8 EFLAGS: 00000246
RAX: ffff888103664c00 RBX: ffffc90000230048 RCX: 0000000000230000
RDX: dffffc0000000000 RSI: ffffffff8474068e RDI: ffffc90000147f48
RBP: ffffc90000230038 R08: ffffc90000230110 R09: ffffc90000230108
R10: 0000000000000008 R11: ffffffff817441e0 R12: 0000000000000000
R13: ffffc90000230098 R14: 1ffff92000046013 R15: ffffc900002305f0
FS: 0000000000000000(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f4df88f7d60 CR3: 00000000072a8000 CR4: 00000000003526b0
Call Trace:
arch_stack_walk+0x139/0x170 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x9d/0xe0 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:48 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:69
kasan_save_free_info+0x4a/0x60 mm/kasan/generic.c:579
poison_slab_object mm/kasan/common.c:248 [inline]
__kasan_slab_free+0x5f/0x80 mm/kasan/common.c:265
kasan_slab_free include/linux/kasan.h:233 [inline]
slab_free_hook mm/slub.c:2418 [inline]
slab_free mm/slub.c:4672 [inline]
kmem_cache_free+0x1c1/0x510 mm/slub.c:4779
kfree_skbmem net/core/skbuff.c:-1 [inline]
__kfree_skb+0x18f/0x210 net/core/skbuff.c:1203
consume_skb+0x65/0x1a0 net/core/skbuff.c:1434
netlink_broadcast_filtered+0x10e1/0x11f0 net/netlink/af_netlink.c:1540
nlmsg_multicast_filtered include/net/netlink.h:1125 [inline]
nlmsg_multicast include/net/netlink.h:1144 [inline]
nlmsg_notify+0xf1/0x1b0 net/netlink/af_netlink.c:2598
rtnl_notify+0x9e/0xd0 net/core/rtnetlink.c:786
fdb_notify+0xce/0x150 net/bridge/br_fdb.c:206
br_fdb_update+0x4b7/0x680 net/bridge/br_fdb.c:941
br_handle_frame_finish+0x39c/0x1720 net/bridge/br_input.c:141
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+0xf48/0x3940 net/core/dev.c:5651
__netif_receive_skb_one_core net/core/dev.c:5755 [inline]
__netif_receive_skb net/core/dev.c:5870 [inline]
process_backlog+0x3e5/0xae0 net/core/dev.c:6206
__napi_poll+0xd0/0x610 net/core/dev.c:6857
napi_poll net/core/dev.c:6926 [inline]
net_rx_action+0x584/0xce0 net/core/dev.c:7048
handle_softirqs+0x1ab/0x630 kernel/softirq.c:621
__do_softirq+0xf/0x16 kernel/softirq.c:659
do_softirq+0xa6/0x100 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+0x5c6/0xd20 kernel/rcu/tree.c:2594
nocb_cb_wait kernel/rcu/tree_nocb.h:923 [inline]
rcu_nocb_cb_kthread+0x4dc/0xac0 kernel/rcu/tree_nocb.h:957
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
net_ratelimit: 51570 callbacks suppressed
ICMPv6: NA: aa:aa:aa:aa:aa:0c advertised our address fe80::a8aa:aaff:feaa:aa0c on bridge0!
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
ICMPv6: NA: aa:aa:aa:aa:aa:0c advertised our address fe80::a8aa:aaff:feaa:aa0c on bridge0!
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
ICMPv6: NA: aa:aa:aa:aa:aa:0c advertised our address fe80::a8aa:aaff:feaa:aa0c on bridge0!
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
ICMPv6: NA: aa:aa:aa:aa:aa:0c advertised our address fe80::a8aa:aaff:feaa:aa0c on bridge0!
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
ICMPv6: NA: aa:aa:aa:aa:aa:0c advertised our address fe80::a8aa:aaff:feaa:aa0c on bridge0!
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)