INFO: task syz.1.1279:4335 blocked for more than 123 seconds. Not tainted 6.12.38-syzkaller-g209015b548fb #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.1.1279 state:D stack:0 pid:4335 tgid:4324 ppid:288 flags:0x00004002 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 tun_detach drivers/net/tun.c:704 [inline] tun_chr_close+0xc5/0x150 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: 0033:0x7f297cd8ebe9 RSP: 002b:00007f297dc03038 EFLAGS: 00000246 ORIG_RAX: 0000000000000036 RAX: fffffffffffffff2 RBX: 00007f297cfb6270 RCX: 00007f297cd8ebe9 RDX: 0000000000000016 RSI: 0000000000000006 RDI: 0000000000000007 RBP: 00007f297ce11e19 R08: 0000000020000328 R09: 0000000000000000 R10: 0000200000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f297cfb6308 R14: 00007f297cfb6270 R15: 00007fff7b12b408 INFO: task syz.2.1294:4372 blocked for more than 123 seconds. Not tainted 6.12.38-syzkaller-g209015b548fb #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.2.1294 state:D stack:0 pid:4372 tgid:4371 ppid:294 flags:0x00004002 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 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: 0033:0x7f5bb0f8ebe9 RSP: 002b:00007f5bb1d69038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: fffffffffffffff0 RBX: 00007f5bb11b5fa0 RCX: 00007f5bb0f8ebe9 RDX: 0000200000002bc0 RSI: 00000000000089a1 RDI: 0000000000000004 RBP: 00007f5bb1011e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f5bb11b6038 R14: 00007f5bb11b5fa0 R15: 00007ffe042b0e98 NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 37 Comm: khungtaskd Not tainted 6.12.38-syzkaller-g209015b548fb #0 c4bb26c31dabe4a25adff9e3720090d1cd174d38 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+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 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 4468 Comm: syz-executor Not tainted 6.12.38-syzkaller-g209015b548fb #0 c4bb26c31dabe4a25adff9e3720090d1cd174d38 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:__unwind_start+0x265/0x410 arch/x86/kernel/unwind_frame.c:-1 Code: d0 83 3b 00 0f 84 3f 01 00 00 48 8b 45 d0 48 8d 48 50 48 8d 50 38 4c 8d 68 08 4c 8d 60 10 48 8b 45 c8 48 83 c0 08 48 89 45 a0 <4d> 89 ee 49 c1 ee 03 4d 89 e7 49 c1 ef 03 48 89 4d a8 48 c1 e9 03 RSP: 0018:ffffc9000022ffd0 EFLAGS: 00000286 RAX: ffffc900002300d8 RBX: ffffc90000230048 RCX: ffffc90000230098 RDX: ffffc90000230080 RSI: 1ffff9200004600a RDI: ffffc900002300a0 RBP: ffffc90000230038 R08: ffffc90000230000 R09: 0000000000000000 R10: ffffc90000230048 R11: fffff52000046015 R12: ffffc90000230058 R13: ffffc90000230050 R14: dffffc0000000000 R15: ffff88811e96df00 FS: 0000555565c24500(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055f67f071b90 CR3: 00000001776e8000 CR4: 00000000003526b0 Call Trace: unwind_start arch/x86/include/asm/unwind.h:64 [inline] arch_stack_walk+0xf3/0x170 arch/x86/kernel/stacktrace.c:24 stack_trace_save+0x9d/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x4a/0x60 mm/kasan/generic.c:579 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2417 [inline] slab_free mm/slub.c:4666 [inline] kmem_cache_free+0x1c1/0x510 mm/slub.c:4773 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+0x10e7/0x1200 net/netlink/af_netlink.c:1527 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:2580 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 __raw_write_unlock_bh include/linux/rwlock_api_smp.h:281 [inline] _raw_write_unlock_bh+0x33/0x70 kernel/locking/spinlock.c:366 neigh_parms_alloc+0x41b/0x5c0 net/core/neighbour.c:1738 inetdev_init+0x14d/0x5d0 net/ipv4/devinet.c:291 inetdev_event+0x555/0x1290 net/ipv4/devinet.c:1579 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+0x115/0x190 net/core/dev.c:2119 register_netdevice+0x12eb/0x19d0 net/core/dev.c:10610 register_netdev+0x42/0x60 net/core/dev.c:10714 ip6_tnl_init_net+0x32b/0x4a0 net/ipv6/ip6_tunnel.c:2271 ops_init+0x1af/0x5d0 net/core/net_namespace.c:139 setup_net+0x20e/0x990 net/core/net_namespace.c:356 copy_net_ns+0x513/0xa30 net/core/net_namespace.c:510 create_new_namespaces+0x3b5/0x720 kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0x126/0x180 kernel/nsproxy.c:228 ksys_unshare+0x4fe/0x880 kernel/fork.c:3352 __do_sys_unshare kernel/fork.c:3423 [inline] __se_sys_unshare kernel/fork.c:3421 [inline] __x64_sys_unshare+0x3c/0x50 kernel/fork.c:3421 x64_sys_call+0x2998/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:273 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x58/0xf0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7f6e87b903e7 Code: 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 10 01 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffeaabe9178 EFLAGS: 00000206 ORIG_RAX: 0000000000000110 RAX: ffffffffffffffda RBX: 00007f6e87db5f40 RCX: 00007f6e87b903e7 RDX: 0000000000000005 RSI: 00007ffeaabe9040 RDI: 0000000040000000 RBP: 00007f6e87db67b8 R08: 00007f6e888e7d60 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000008 R13: 0000000000000003 R14: 0000000000000009 R15: 0000000000000000 net_ratelimit: 95545 callbacks suppressed bridge0: received packet on veth0_to_bridge with own address as source address (addr:e6:d6:cc:d9:66:c6, 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:e6:d6:cc:d9:66:c6, 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:e6:d6:cc:d9:66:c6, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)