INFO: task syz.2.121:737 blocked for more than 123 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.2.121 state:D stack:0 pid:737 tgid:737 ppid:299 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:6060 [inline] __schedule+0x1496/0x20b0 kernel/sched/core.c:7873 __schedule_loop kernel/sched/core.c:7950 [inline] schedule+0xc5/0x240 kernel/sched/core.c:7965 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:8022 __mutex_lock_common kernel/locking/mutex.c:707 [inline] __mutex_lock+0x902/0x1b90 kernel/locking/mutex.c:806 __mutex_lock_slowpath+0xe/0x20 kernel/locking/mutex.c:1136 mutex_lock+0x113/0x1d0 kernel/locking/mutex.c:285 rcu_barrier+0x4d/0x580 kernel/rcu/tree.c:4589 netdev_run_todo+0x118/0xce0 net/core/dev.c:10912 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:3520 __fput+0x20b/0xa30 fs/file_table.c:447 ____fput+0x20/0x30 fs/file_table.c:475 task_work_run+0x1e8/0x260 kernel/task_work.c:246 exit_task_work include/linux/task_work.h:43 [inline] do_exit+0xa46/0x2850 kernel/exit.c:955 do_group_exit+0x21f/0x2f0 kernel/exit.c:1098 get_signal+0x134c/0x1490 kernel/signal.c:2933 arch_do_signal_or_restart+0xbc/0x700 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+0x57/0xb0 kernel/entry/common.c:218 do_syscall_64+0x63/0xf0 arch/x86/entry/common.c:84 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7faf50f5e6ce RSP: 002b:00007faf51f02f58 EFLAGS: 00000246 ORIG_RAX: 00000000000000e6 RAX: fffffffffffffdfc RBX: 00007faf51f036c0 RCX: 00007faf50f5e6ce RDX: 00007faf51f02fb0 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007faf51033eaf R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007faf51226038 R14: 00007faf51225fa0 R15: 00007ffdb6a3e188 INFO: task syz.0.195:1012 blocked for more than 127 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.0.195 state:D stack:0 pid:1012 tgid:1012 ppid:294 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:6060 [inline] __schedule+0x1496/0x20b0 kernel/sched/core.c:7873 __schedule_loop kernel/sched/core.c:7950 [inline] schedule+0xc5/0x240 kernel/sched/core.c:7965 schedule_timeout+0xc7/0x3b0 kernel/time/timer.c:2596 do_wait_for_common kernel/sched/completion.c:95 [inline] __wait_for_common kernel/sched/completion.c:116 [inline] wait_for_common+0x368/0x650 kernel/sched/completion.c:127 wait_for_completion+0x1c/0x40 kernel/sched/completion.c:148 exit_aio+0x28d/0x360 fs/aio.c:927 __mmput+0x2f/0x330 kernel/fork.c:1367 mmput+0x55/0x170 kernel/fork.c:1394 exit_mm kernel/exit.c:575 [inline] do_exit+0x9a5/0x2850 kernel/exit.c:942 do_group_exit+0x21f/0x2f0 kernel/exit.c:1098 __do_sys_exit_group kernel/exit.c:1109 [inline] __se_sys_exit_group kernel/exit.c:1107 [inline] __x64_sys_exit_group+0x43/0x50 kernel/exit.c:1107 x64_sys_call+0x2ed2/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/common.c:47 [inline] do_syscall_64+0x57/0xf0 arch/x86/entry/common.c:78 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7fb0bb79de99 RSP: 002b:00007ffd85c2da48 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fb0bb79de99 RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007ffd85c2daac R08: 0000000000000000 R09: 00000000000927c0 R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000036 R13: 00000000000927c0 R14: 00000000000682b1 R15: 00007ffd85c2db00 NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 e661c05697932dc72467e0ff9a1babb7f2c48647 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 Call Trace: __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+0xe45/0xf90 kernel/hung_task.c:423 kthread+0x2c7/0x360 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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 1033 Comm: syz-executor Not tainted syzkaller #0 e661c05697932dc72467e0ff9a1babb7f2c48647 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 RIP: 0010:ip6_frag_queue net/ipv6/reassembly.c:130 [inline] RIP: 0010:ipv6_frag_rcv+0xcf1/0x27d0 net/ipv6/reassembly.c:391 Code: c1 c0 08 48 8b 5c 24 68 48 83 c3 08 48 89 94 24 f8 00 00 00 89 d1 29 d9 0f b7 c0 01 c8 45 8d 74 07 28 bf ff ff 00 00 44 89 f6 1a ae 84 fc 41 81 fe 00 00 01 00 0f 82 38 01 00 00 e8 c8 a9 84 RSP: 0018:ffffc90000007020 EFLAGS: 00000282 RAX: 00000000f74882b0 RBX: ffff888108b7b040 RCX: 00000000f7487d00 RDX: 0000000000002d40 RSI: 00000000000032e8 RDI: 000000000000ffff RBP: ffffc90000007230 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff52000000df4 R12: ffff88814130d5e0 R13: 1ffff110248f654c R14: 00000000000032e8 R15: ffff888108b7b010 FS: 000055558e564500(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000555555b01898 CR3: 0000000113c98000 CR4: 00000000003526b0 Call Trace: ip6_protocol_deliver_rcu+0xbc0/0x1270 net/ipv6/ip6_input.c:436 ip6_input_finish net/ipv6/ip6_input.c:481 [inline] NF_HOOK include/linux/netfilter.h:317 [inline] ip6_input+0x1c3/0x3a0 net/ipv6/ip6_input.c:490 ip6_mc_input+0x333/0x680 net/ipv6/ip6_input.c:584 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+0xf1/0x240 net/ipv6/ip6_input.c:309 __netif_receive_skb_one_core net/core/dev.c:5801 [inline] __netif_receive_skb net/core/dev.c:5914 [inline] netif_receive_skb_internal net/core/dev.c:6000 [inline] netif_receive_skb+0x146/0x7b0 net/core/dev.c:6059 br_netif_receive_skb net/bridge/br_input.c:30 [inline] NF_HOOK include/linux/netfilter.h:317 [inline] br_pass_frame_up+0x126/0x1b0 net/bridge/br_input.c:70 br_handle_frame_finish+0x1178/0x1620 net/bridge/br_input.c:-1 nf_hook_bridge_pre net/bridge/br_input.c:301 [inline] br_handle_frame+0x5a5/0xba0 net/bridge/br_input.c:424 __netif_receive_skb_core+0xfc4/0x3a70 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+0x40b/0xaf0 net/core/dev.c:6250 __napi_poll+0xd0/0x600 net/core/dev.c:6901 napi_poll net/core/dev.c:6970 [inline] net_rx_action+0x5dc/0xd70 net/core/dev.c:7092 handle_softirqs+0x1aa/0x620 kernel/softirq.c:621 __do_softirq+0xf/0x16 kernel/softirq.c:659 do_softirq+0xb8/0x110 kernel/softirq.c:503 __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+0x60d/0x1970 net/ipv6/addrconf.c:3950 addrconf_notify+0x17a/0xeb0 net/ipv6/addrconf.c:-1 notifier_call_chain+0x106/0x2b0 kernel/notifier.c:93 raw_notifier_call_chain+0x31/0x40 kernel/notifier.c:461 call_netdevice_notifiers_info net/core/dev.c:2074 [inline] call_netdevice_notifiers_extack net/core/dev.c:2112 [inline] call_netdevice_notifiers net/core/dev.c:2126 [inline] unregister_netdevice_many_notify+0xde1/0x1be0 net/core/dev.c:11533 unregister_netdevice_many+0x1d/0x30 net/core/dev.c:11595 setup_net+0x5e5/0x9b0 net/core/net_namespace.c:383 copy_net_ns+0x4fc/0xa20 net/core/net_namespace.c:510 create_new_namespaces+0x390/0x6f0 kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0x124/0x180 kernel/nsproxy.c:228 ksys_unshare+0x4f9/0x8f0 kernel/fork.c:3385 __do_sys_unshare kernel/fork.c:3468 [inline] __se_sys_unshare kernel/fork.c:3466 [inline] __x64_sys_unshare+0x3c/0x50 kernel/fork.c:3466 x64_sys_call+0x2998/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:273 do_syscall_x64 arch/x86/entry/common.c:47 [inline] do_syscall_64+0x57/0xf0 arch/x86/entry/common.c:78 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7f3b3279f167 Code: 73 01 c3 48 c7 c1 e8 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffef19bc088 EFLAGS: 00000202 ORIG_RAX: 0000000000000110 RAX: ffffffffffffffda RBX: 00007f3b32a25f40 RCX: 00007f3b3279f167 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000040000000 RBP: 00007f3b32a267b8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000008 R13: 0000000000000003 R14: 00007ffef19bc2c8 R15: 0000000000000000 net_ratelimit: 129829 callbacks suppressed 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 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:0c, vlan:0) bridge0: received packet on veth0_to_bridge with own address as source address (addr:2a:b5:d8:c9:be:ff, 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 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)