INFO: task syz.0.1237:4202 blocked for more than 123 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.0.1237 state:D stack:0 pid:4202 tgid:4202 ppid:293 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:6026 [inline] __schedule+0x14ce/0x2100 kernel/sched/core.c:7893 __schedule_loop kernel/sched/core.c:7974 [inline] schedule+0xc5/0x240 kernel/sched/core.c:7989 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+0x369/0x650 kernel/sched/completion.c:127 wait_for_completion+0x1c/0x40 kernel/sched/completion.c:148 exit_aio+0x2ec/0x3c0 fs/aio.c:927 __mmput+0x30/0x340 kernel/fork.c:1356 mmput+0x55/0x170 kernel/fork.c:1383 exit_mm kernel/exit.c:574 [inline] do_exit+0x909/0x2720 kernel/exit.c:941 do_group_exit+0x229/0x2f0 kernel/exit.c:1096 __do_sys_exit_group kernel/exit.c:1107 [inline] __se_sys_exit_group kernel/exit.c:1105 [inline] __x64_sys_exit_group+0x43/0x50 kernel/exit.c:1105 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: 0033:0x7f708d59ce59 RSP: 002b:00007fff185011b8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f708d59ce59 RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007fff1850121c R08: 0000000000000000 R09: 00000000000927c0 R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000131 R13: 00000000000927c0 R14: 00000000000237f8 R15: 00007fff18501270 NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 abd407d91653e73ff3b9de718fd37c0b8ddb7a3a Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 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+0xdad/0xf00 kernel/hung_task.c:423 kthread+0x2c9/0x370 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 1 to CPUs 0: net_ratelimit: 147622 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:e6:ca:c3:17:6a:28, 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 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:ca:c3:17:6a:28, 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:ca:c3:17:6a:28, vlan:0) NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 4242 Comm: syz-executor Not tainted syzkaller #0 abd407d91653e73ff3b9de718fd37c0b8ddb7a3a Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:update_stack_state+0x381/0x4b0 arch/x86/kernel/unwind_frame.c:244 Code: 4c 89 f7 e8 81 96 9b 00 48 8b 45 d0 49 89 06 48 8b 45 98 42 80 3c 20 00 4c 8b 75 c8 4c 8b 6d c0 74 08 4c 89 f7 e8 5f 96 9b 00 <49> c7 06 00 00 00 00 48 83 45 d0 08 eb 0c 48 83 e8 80 48 89 45 d0 RSP: 0018:ffffc90000007418 EFLAGS: 00000246 RAX: 1ffff92000000eb8 RBX: ffffc90000007568 RCX: ffffc90000007901 RDX: ffffc90000007998 RSI: 1ffff92000000eae RDI: ffffc900000075c0 RBP: ffffc900000074d8 R08: ffffc90000007630 R09: ffffc90000007628 R10: 0000000000000004 R11: ffffffff8175f3a0 R12: dffffc0000000000 R13: ffffc90000007590 R14: ffffc900000075c0 R15: 1ffff92000000eb5 FS: 0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f7f8ed47e20 CR3: 000000010abf0000 CR4: 00000000003526b0 DR0: 0000000000000004 DR1: 0000000000000000 DR2: 000000000000000a DR3: 0000000000000800 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: unwind_next_frame+0x3c1/0x750 arch/x86/kernel/unwind_frame.c:315 arch_stack_walk+0x138/0x170 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:49 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:70 kasan_save_free_info+0x4a/0x60 mm/kasan/generic.c:579 poison_slab_object mm/kasan/common.c:249 [inline] __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:266 kasan_slab_free include/linux/kasan.h:234 [inline] slab_free_hook mm/slub.c:2445 [inline] slab_free mm/slub.c:4714 [inline] kmem_cache_free+0x1bd/0x4f0 mm/slub.c:4825 kfree_skbmem net/core/skbuff.c:-1 [inline] __kfree_skb+0x18f/0x210 net/core/skbuff.c:1203 sk_skb_reason_drop+0xd8/0x310 net/core/skbuff.c:1240 kfree_skb_reason include/linux/skbuff.h:1303 [inline] kfree_skb include/linux/skbuff.h:1312 [inline] ip6_mc_input+0x516/0x6c0 net/ipv6/ip6_input.c:587 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] process_backlog+0x44b/0xad0 net/core/dev.c:6250 __napi_poll+0xd0/0x610 net/core/dev.c:6901 napi_poll net/core/dev.c:6970 [inline] net_rx_action+0x5ea/0xd80 net/core/dev.c:7092 handle_softirqs+0x1aa/0x630 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+0x614/0x1980 net/ipv6/addrconf.c:3950 addrconf_notify+0x17a/0xea0 net/ipv6/addrconf.c:-1 notifier_call_chain+0x10e/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+0xe3f/0x1c30 net/core/dev.c:11533 unregister_netdevice_many net/core/dev.c:11595 [inline] unregister_netdevice_queue+0x341/0x390 net/core/dev.c:11469 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:3520 __fput+0x1fe/0xa00 fs/file_table.c:429 ____fput+0x20/0x30 fs/file_table.c:457 task_work_run+0x1e5/0x260 kernel/task_work.c:246 exit_task_work include/linux/task_work.h:43 [inline] do_exit+0x9ad/0x2720 kernel/exit.c:954 do_group_exit+0x229/0x2f0 kernel/exit.c:1096 get_signal+0x1398/0x14e0 kernel/signal.c:2933 arch_do_signal_or_restart+0xbc/0x760 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: 0033:0x7f7217757fd7 Code: Unable to access opcode bytes at 0x7f7217757fad. RSP: 002b:00007ffe91974f30 EFLAGS: 00000202 ORIG_RAX: 000000000000002c RAX: 000000000000002c RBX: 0000555593a4d500 RCX: 00007f7217757fd7 RDX: 000000000000002c RSI: 00007f7218544670 RDI: 0000000000000003 RBP: 0000000000000001 R08: 00007ffe91974f94 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000003 R13: 0000000000000000 R14: 00007f7218544670 R15: 0000000000000000 net_ratelimit: 154488 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:e6:ca:c3:17:6a:28, 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 veth0_to_bridge with own address as source address (addr:e6:ca:c3:17:6a:28, 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:ca:c3:17:6a:28, vlan:0)