syzbot

INFO: task syz.1.155:852 blocked for more than 123 seconds.
      Not tainted 6.12.38-syzkaller-g3f3a5c5e782d #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.155       state:D stack:0     pid:852   tgid:849   ppid:289    flags:0x00004000
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
 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
 exit_aio+0x2df/0x3b0 fs/aio.c:927
 __mmput+0x30/0x320 kernel/fork.c:1346
 mmput+0x55/0x170 kernel/fork.c:1372
 exit_mm kernel/exit.c:574 [inline]
 do_exit+0x918/0x2630 kernel/exit.c:940
 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: 0033:0x7f85e6f8ebe9
RSP: 002b:00007f85e7e44038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: 0000000000000000 RBX: 00007f85e71b5fa0 RCX: 00007f85e6f8ebe9
RDX: 0000000000000000 RSI: 000000000000ae60 RDI: 0000000000000025
RBP: 00007f85e7011e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f85e71b6038 R14: 00007f85e71b5fa0 R15: 00007fffb6928248
 </TASK>
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 37 Comm: khungtaskd Not tainted 6.12.38-syzkaller-g3f3a5c5e782d #0 c9247809a66a5ebb3467d1c2e99b1dedbd707993
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+0x2ca/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:
net_ratelimit: 105929 callbacks suppressed
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:5e:83:4e:e1:a4:41, 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:5e:83:4e:e1:a4:41, 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:5e:83:4e:e1:a4:41, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 875 Comm: syz-executor Not tainted 6.12.38-syzkaller-g3f3a5c5e782d #0 c9247809a66a5ebb3467d1c2e99b1dedbd707993
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:arch_atomic_read arch/x86/include/asm/atomic.h:23 [inline]
RIP: 0010:raw_atomic_read include/linux/atomic/atomic-arch-fallback.h:457 [inline]
RIP: 0010:atomic_read include/linux/atomic/atomic-instrumented.h:33 [inline]
RIP: 0010:ip6_mc_input+0x2d1/0x670 net/ipv6/ip6_input.c:529
Code: 00 00 fc ff df 80 3c 08 00 74 08 4c 89 e7 e8 16 9c fa fc 41 be 9c 00 00 00 4d 03 34 24 4c 89 f7 be 04 00 00 00 e8 cf 9e fa fc <4c> 89 f0 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 0f b6 04 08 84
RSP: 0018:ffffc900000079e0 EFLAGS: 00000256
RAX: 1ffff11024a70701 RBX: ffff888117e1c8d0 RCX: ffffffff84e169c1
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff8881253b489c
RBP: ffffc90000007ab8 R08: ffff8881253b489f R09: 1ffff11024a76913
R10: dffffc0000000000 R11: ffffed1024a76914 R12: ffff888125383d40
R13: ffff88813e5b6328 R14: ffff8881253b489c R15: ffff88812fefa118
FS:  0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffcc0e29c4c CR3: 000000012d66e000 CR4: 00000000003526b0
Call Trace:
 <IRQ>
 dst_input include/net/dst.h:469 [inline]
 ip6_rcv_finish+0x344/0x3c0 net/ipv6/ip6_input.c:79
 NF_HOOK include/linux/netfilter.h:317 [inline]
 ipv6_rcv+0xed/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+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
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x74/0x80 kernel/softirq.c:430
 __raw_spin_unlock_bh include/linux/spinlock_api_smp.h:167 [inline]
 _raw_spin_unlock_bh+0x54/0x60 kernel/locking/spinlock.c:210
 spin_unlock_bh include/linux/spinlock.h:396 [inline]
 addrconf_ifdown+0x608/0x1940 net/ipv6/addrconf.c:3956
 addrconf_notify+0x17a/0xea0 net/ipv6/addrconf.c:-1
 notifier_call_chain+0x10b/0x2c0 kernel/notifier.c:93
 raw_notifier_call_chain+0x31/0x40 kernel/notifier.c:461
 call_netdevice_notifiers_info net/core/dev.c:2067 [inline]
 call_netdevice_notifiers_extack net/core/dev.c:2105 [inline]
 call_netdevice_notifiers net/core/dev.c:2119 [inline]
 unregister_netdevice_many_notify+0xe32/0x1bd0 net/core/dev.c:11489
 unregister_netdevice_many net/core/dev.c:11551 [inline]
 unregister_netdevice_queue+0x339/0x380 net/core/dev.c:11425
 unregister_netdevice include/linux/netdevice.h:3165 [inline]
 __tun_detach+0xca1/0x1460 drivers/net/tun.c:685
 tun_detach drivers/net/tun.c:701 [inline]
 tun_chr_close+0x93/0x150 drivers/net/tun.c:3517
 __fput+0x1fb/0xa00 fs/file_table.c:429
 ____fput+0x20/0x30 fs/file_table.c:457
 task_work_run+0x1e0/0x250 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: 0033:0x7fdf07b90a23
Code: Unable to access opcode bytes at 0x7fdf07b909f9.
RSP: 002b:00007ffc5b12dab8 EFLAGS: 00000202 ORIG_RAX: 000000000000002c
RAX: 0000000000000068 RBX: 00007fdf088e4620 RCX: 00007fdf07b90a23
RDX: 0000000000000068 RSI: 00007fdf088e4670 RDI: 0000000000000003
RBP: 0000000000000001 R08: 00007ffc5b12dad4 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000003
R13: 0000000000000000 R14: 00007fdf088e4670 R15: 0000000000000000
 </TASK>
net_ratelimit: 105303 callbacks suppressed
bridge0: received packet on veth0_to_bridge with own address as source address (addr:5e:83:4e:e1:a4:41, 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:5e:83:4e:e1:a4:41, 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 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 bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)