syzbot

INFO: task syz.6.4409:12988 blocked for more than 123 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.4409      state:D stack:0     pid:12988 tgid:12988 ppid:7111   flags:0x00004004
Call Trace:
 <TASK>
 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
 synchronize_rcu_expedited+0x6b0/0x7b0 kernel/rcu/tree_exp.h:991
 synchronize_rcu+0x77/0x2e0 kernel/rcu/tree.c:4119
 synchronize_net+0x38/0x40 net/core/dev.c:11370
 packet_release+0x9f8/0xd50 net/packet/af_packet.c:3216
 __sock_release net/socket.c:659 [inline]
 sock_close+0xda/0x280 net/socket.c:1427
 __fput+0x1fb/0xa00 fs/file_table.c:429
 ____fput+0x20/0x30 fs/file_table.c:457
 task_work_run+0x1e3/0x250 kernel/task_work.c:240
 resume_user_mode_work+0x36/0x50 include/linux/resume_user_mode.h:50
 exit_to_user_mode_loop kernel/entry/common.c:114 [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+0x64/0xb0 kernel/entry/common.c:218
 do_syscall_64+0x64/0xf0 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7fa700b8ebe9
RSP: 002b:00007ffc61b61c68 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007fa700dc7da0 RCX: 00007fa700b8ebe9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007fa700dc7da0 R08: 0000000000000134 R09: 0000001161b61f5f
R10: 00000000003ffca8 R11: 0000000000000246 R12: 000000000004e3e7
R13: 00007fa700dc6090 R14: ffffffffffffffff R15: 00007ffc61b61d80
 </TASK>
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 e0010524de270d562e17ec59754923f7dbe680d3
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <TASK>
 __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
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 450 Comm: kworker/1:3 Not tainted syzkaller #0 e0010524de270d562e17ec59754923f7dbe680d3
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Workqueue: events_power_efficient neigh_periodic_work
RIP: 0010:should_resched arch/x86/include/asm/preempt.h:103 [inline]
RIP: 0010:__local_bh_enable_ip+0x54/0x80 kernel/softirq.c:437
Code: 7e 65 8b 05 66 fa b4 7e a9 00 ff ff 00 75 0d 65 66 8b 05 77 fa b4 7e 66 85 c0 75 29 65 ff 0d 4b fa b4 7e 65 8b 05 44 fa b4 7e <85> c0 74 07 5d e9 52 aa 3e 04 cc e8 9c 09 ba ff 5d e9 46 aa 3e 04
RSP: 0018:ffffc90000230770 EFLAGS: 00000282
RAX: 0000000080000101 RBX: 0000000000000001 RCX: ffff888115e81300
RDX: 0000000000000100 RSI: 0000000000000200 RDI: ffffffff84f4ad2c
RBP: ffffc90000230770 R08: ffff888131e6b000 R09: 0000000000000000
R10: ffffc900002308d0 R11: fffff5200004611e R12: ffff888131e6b0f0
R13: dffffc0000000000 R14: ffff888131e6b040 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f230f393ad8 CR3: 00000000072a8000 CR4: 00000000003526b0
Call Trace:
 <IRQ>
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 ip6t_do_table+0x1305/0x14d0 net/ipv6/netfilter/ip6_tables.c:375
 ip6table_mangle_hook+0x29a/0x6b0 net/ipv6/netfilter/ip6table_mangle.c:73
 nf_hook_entry_hookfn include/linux/netfilter.h:155 [inline]
 nf_hook_slow+0xd2/0x240 net/netfilter/core.c:626
 nf_hook include/linux/netfilter.h:272 [inline]
 NF_HOOK include/linux/netfilter.h:315 [inline]
 ipv6_rcv+0x1c7/0x220 net/ipv6/ip6_input.c:309
 __netif_receive_skb_one_core net/core/dev.c:5757 [inline]
 __netif_receive_skb net/core/dev.c:5870 [inline]
 process_backlog+0x44b/0xae0 net/core/dev.c:6206
 __napi_poll+0xd3/0x610 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
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x74/0x80 kernel/softirq.c:430
 __raw_write_unlock_bh include/linux/rwlock_api_smp.h:281 [inline]
 _raw_write_unlock_bh+0x33/0x70 kernel/locking/spinlock.c:366
 neigh_periodic_work+0xa73/0xbc0 net/core/neighbour.c:1019
 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
 </TASK>
net_ratelimit: 74895 callbacks suppressed
bridge0: received packet on veth0_to_bridge with own address as source address (addr:e2:29:89:0b:24:47, 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: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:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:e2:29:89:0b:24:47, 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)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
net_ratelimit: 89921 callbacks suppressed
bridge0: received packet on veth0_to_bridge with own address as source address (addr:e2:29:89:0b:24:47, 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: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:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:e2:29:89:0b:24:47, 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)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)