INFO: task kworker/u8:1:13 blocked for more than 122 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u8:1 state:D stack:0 pid:13 tgid:13 ppid:2 flags:0x00004000 Workqueue: ipv6_addrconf addrconf_dad_work Call Trace: context_switch kernel/sched/core.c:5996 [inline] __schedule+0x134f/0x1ea0 kernel/sched/core.c:7843 __schedule_loop kernel/sched/core.c:7924 [inline] schedule+0xc5/0x240 kernel/sched/core.c:7939 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:7996 __mutex_lock_common kernel/locking/mutex.c:707 [inline] __mutex_lock+0x960/0x1bb0 kernel/locking/mutex.c:803 __mutex_lock_slowpath+0xe/0x20 kernel/locking/mutex.c:1134 mutex_lock+0x113/0x1d0 kernel/locking/mutex.c:285 rtnl_lock+0x19/0x20 net/core/rtnetlink.c:79 addrconf_dad_work+0xce/0x1530 net/ipv6/addrconf.c:4234 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0x7d4/0x1020 kernel/workqueue.c:3319 worker_thread+0xc70/0x10b0 kernel/workqueue.c:3400 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 INFO: task kworker/u8:5:424 blocked for more than 123 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u8:5 state:D stack:0 pid:424 tgid:424 ppid:2 flags:0x00004000 Workqueue: events_unbound linkwatch_event Call Trace: context_switch kernel/sched/core.c:5996 [inline] __schedule+0x134f/0x1ea0 kernel/sched/core.c:7843 __schedule_loop kernel/sched/core.c:7924 [inline] schedule+0xc5/0x240 kernel/sched/core.c:7939 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:7996 __mutex_lock_common kernel/locking/mutex.c:707 [inline] __mutex_lock+0x960/0x1bb0 kernel/locking/mutex.c:803 __mutex_lock_slowpath+0xe/0x20 kernel/locking/mutex.c:1134 mutex_lock+0x113/0x1d0 kernel/locking/mutex.c:285 rtnl_lock+0x19/0x20 net/core/rtnetlink.c:79 linkwatch_event+0x12/0x60 net/core/link_watch.c:285 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0x7d4/0x1020 kernel/workqueue.c:3319 worker_thread+0xc70/0x10b0 kernel/workqueue.c:3400 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 INFO: task syz-executor:507 blocked for more than 124 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:0 pid:507 tgid:507 ppid:1 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:5996 [inline] __schedule+0x134f/0x1ea0 kernel/sched/core.c:7843 __schedule_loop kernel/sched/core.c:7924 [inline] schedule+0xc5/0x240 kernel/sched/core.c:7939 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:7996 __mutex_lock_common kernel/locking/mutex.c:707 [inline] __mutex_lock+0x960/0x1bb0 kernel/locking/mutex.c:803 __mutex_lock_slowpath+0xe/0x20 kernel/locking/mutex.c:1134 mutex_lock+0x113/0x1d0 kernel/locking/mutex.c:285 rtnl_lock net/core/rtnetlink.c:79 [inline] rtnetlink_rcv_msg+0x79e/0xa40 net/core/rtnetlink.c:6672 netlink_rcv_skb+0x256/0x4f0 net/netlink/af_netlink.c:2545 rtnetlink_rcv+0x20/0x30 net/core/rtnetlink.c:6693 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline] netlink_unicast+0x8c0/0xa60 net/netlink/af_netlink.c:1339 netlink_sendmsg+0x7fe/0xb10 net/netlink/af_netlink.c:1889 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] __sys_sendto+0x718/0x790 net/socket.c:2217 __do_sys_sendto net/socket.c:2229 [inline] __se_sys_sendto net/socket.c:2225 [inline] __x64_sys_sendto+0xe9/0x100 net/socket.c:2225 x64_sys_call+0x2c2c/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:45 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: 0033:0x7f2aab9560d7 RSP: 002b:00007ffea6080a20 EFLAGS: 00000202 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 0000555594f9c500 RCX: 00007f2aab9560d7 RDX: 000000000000002c RSI: 00007f2aac744670 RDI: 0000000000000003 RBP: 0000000000000001 R08: 00007ffea6080a84 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000003 R13: 0000000000000000 R14: 00007f2aac744670 R15: 0000000000000000 INFO: task syz-executor:510 blocked for more than 125 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:0 pid:510 tgid:510 ppid:1 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:5996 [inline] __schedule+0x134f/0x1ea0 kernel/sched/core.c:7843 __schedule_loop kernel/sched/core.c:7924 [inline] schedule+0xc5/0x240 kernel/sched/core.c:7939 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:7996 __mutex_lock_common kernel/locking/mutex.c:707 [inline] __mutex_lock+0x960/0x1bb0 kernel/locking/mutex.c:803 __mutex_lock_slowpath+0xe/0x20 kernel/locking/mutex.c:1134 mutex_lock+0x113/0x1d0 kernel/locking/mutex.c:285 rtnl_lock net/core/rtnetlink.c:79 [inline] rtnetlink_rcv_msg+0x79e/0xa40 net/core/rtnetlink.c:6672 netlink_rcv_skb+0x256/0x4f0 net/netlink/af_netlink.c:2545 rtnetlink_rcv+0x20/0x30 net/core/rtnetlink.c:6693 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline] netlink_unicast+0x8c0/0xa60 net/netlink/af_netlink.c:1339 netlink_sendmsg+0x7fe/0xb10 net/netlink/af_netlink.c:1889 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] __sys_sendto+0x718/0x790 net/socket.c:2217 __do_sys_sendto net/socket.c:2229 [inline] __se_sys_sendto net/socket.c:2225 [inline] __x64_sys_sendto+0xe9/0x100 net/socket.c:2225 x64_sys_call+0x2c2c/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:45 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: 0033:0x7f66101560d7 RSP: 002b:00007ffda67c99e0 EFLAGS: 00000202 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 000055557db8e500 RCX: 00007f66101560d7 RDX: 0000000000000028 RSI: 00007f6610f44670 RDI: 0000000000000003 RBP: 0000000000000001 R08: 00007ffda67c9a44 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000003 R13: 0000000000000000 R14: 00007f6610f44670 R15: 0000000000000000 INFO: task syz-executor:511 blocked for more than 126 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:0 pid:511 tgid:511 ppid:1 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5996 [inline] __schedule+0x134f/0x1ea0 kernel/sched/core.c:7843 __schedule_loop kernel/sched/core.c:7924 [inline] schedule+0xc5/0x240 kernel/sched/core.c:7939 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:7996 __mutex_lock_common kernel/locking/mutex.c:707 [inline] __mutex_lock+0x960/0x1bb0 kernel/locking/mutex.c:803 __mutex_lock_slowpath+0xe/0x20 kernel/locking/mutex.c:1134 mutex_lock+0x113/0x1d0 kernel/locking/mutex.c:285 rtnl_lock net/core/rtnetlink.c:79 [inline] rtnetlink_rcv_msg+0x79e/0xa40 net/core/rtnetlink.c:6672 netlink_rcv_skb+0x256/0x4f0 net/netlink/af_netlink.c:2545 rtnetlink_rcv+0x20/0x30 net/core/rtnetlink.c:6693 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline] netlink_unicast+0x8c0/0xa60 net/netlink/af_netlink.c:1339 netlink_sendmsg+0x7fe/0xb10 net/netlink/af_netlink.c:1889 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] __sys_sendto+0x718/0x790 net/socket.c:2217 __do_sys_sendto net/socket.c:2229 [inline] __se_sys_sendto net/socket.c:2225 [inline] __x64_sys_sendto+0xe9/0x100 net/socket.c:2225 x64_sys_call+0x2c2c/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:45 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: 0033:0x7f5de0b560d7 RSP: 002b:00007fff1c3d3560 EFLAGS: 00000202 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 0000555558c9b500 RCX: 00007f5de0b560d7 RDX: 0000000000000028 RSI: 00007f5de1944670 RDI: 0000000000000003 RBP: 0000000000000001 R08: 00007fff1c3d35c4 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000003 R13: 0000000000000000 R14: 00007f5de1944670 R15: 0000000000000000 INFO: task syz-executor:513 blocked for more than 127 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:0 pid:513 tgid:513 ppid:1 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:5996 [inline] __schedule+0x134f/0x1ea0 kernel/sched/core.c:7843 __schedule_loop kernel/sched/core.c:7924 [inline] schedule+0xc5/0x240 kernel/sched/core.c:7939 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:7996 __mutex_lock_common kernel/locking/mutex.c:707 [inline] __mutex_lock+0x960/0x1bb0 kernel/locking/mutex.c:803 __mutex_lock_slowpath+0xe/0x20 kernel/locking/mutex.c:1134 mutex_lock+0x113/0x1d0 kernel/locking/mutex.c:285 rtnl_lock net/core/rtnetlink.c:79 [inline] rtnetlink_rcv_msg+0x79e/0xa40 net/core/rtnetlink.c:6672 netlink_rcv_skb+0x256/0x4f0 net/netlink/af_netlink.c:2545 rtnetlink_rcv+0x20/0x30 net/core/rtnetlink.c:6693 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline] netlink_unicast+0x8c0/0xa60 net/netlink/af_netlink.c:1339 netlink_sendmsg+0x7fe/0xb10 net/netlink/af_netlink.c:1889 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] __sys_sendto+0x718/0x790 net/socket.c:2217 __do_sys_sendto net/socket.c:2229 [inline] __se_sys_sendto net/socket.c:2225 [inline] __x64_sys_sendto+0xe9/0x100 net/socket.c:2225 x64_sys_call+0x2c2c/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:45 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: 0033:0x7f63549560d7 RSP: 002b:00007fff62b09500 EFLAGS: 00000202 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 000055556e44c500 RCX: 00007f63549560d7 RDX: 0000000000000028 RSI: 00007f6355744670 RDI: 0000000000000003 RBP: 0000000000000001 R08: 00007fff62b09564 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000003 R13: 0000000000000000 R14: 00007f6355744670 R15: 0000000000000000 INFO: task syz-executor:515 blocked for more than 128 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:0 pid:515 tgid:515 ppid:1 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:5996 [inline] __schedule+0x134f/0x1ea0 kernel/sched/core.c:7843 __schedule_loop kernel/sched/core.c:7924 [inline] schedule+0xc5/0x240 kernel/sched/core.c:7939 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:7996 __mutex_lock_common kernel/locking/mutex.c:707 [inline] __mutex_lock+0x960/0x1bb0 kernel/locking/mutex.c:803 __mutex_lock_slowpath+0xe/0x20 kernel/locking/mutex.c:1134 mutex_lock+0x113/0x1d0 kernel/locking/mutex.c:285 rtnl_lock net/core/rtnetlink.c:79 [inline] rtnetlink_rcv_msg+0x79e/0xa40 net/core/rtnetlink.c:6672 netlink_rcv_skb+0x256/0x4f0 net/netlink/af_netlink.c:2545 rtnetlink_rcv+0x20/0x30 net/core/rtnetlink.c:6693 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline] netlink_unicast+0x8c0/0xa60 net/netlink/af_netlink.c:1339 netlink_sendmsg+0x7fe/0xb10 net/netlink/af_netlink.c:1889 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] __sys_sendto+0x718/0x790 net/socket.c:2217 __do_sys_sendto net/socket.c:2229 [inline] __se_sys_sendto net/socket.c:2225 [inline] __x64_sys_sendto+0xe9/0x100 net/socket.c:2225 x64_sys_call+0x2c2c/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:45 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: 0033:0x7faa795560d7 RSP: 002b:00007ffedfada110 EFLAGS: 00000202 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 000055558aa0b500 RCX: 00007faa795560d7 RDX: 0000000000000028 RSI: 00007faa7a344670 RDI: 0000000000000003 RBP: 0000000000000001 R08: 00007ffedfada174 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000003 R13: 0000000000000000 R14: 00007faa7a344670 R15: 0000000000000000 NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 ca1356f2cd16bfc15aeb7d3d887f3f77f8f4461b Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 30 Comm: ksoftirqd/1 Not tainted syzkaller #0 ca1356f2cd16bfc15aeb7d3d887f3f77f8f4461b Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:br_dev_queue_push_xmit+0xad/0x700 net/bridge/br_forward.c:41 Code: 49 8d 7d 10 48 89 f8 48 c1 e8 03 80 3c 18 00 74 05 e8 67 98 cf fc 49 8b 7d 10 4c 89 ee e8 ab 61 6b ff 84 c0 0f 84 8b 00 00 00 <49> 8d 9d 80 00 00 00 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc RSP: 0018:ffffc900001f73e0 EFLAGS: 00000202 RAX: 000000000ea5e001 RBX: dffffc0000000000 RCX: ffff88810367cc00 RDX: 0000000000000100 RSI: 00000000000005ee RDI: 0000000000000056 RBP: ffffc900001f74b8 R08: ffff88813172aba3 R09: 1ffff110262e5574 R10: dffffc0000000000 R11: ffffed10262e5575 R12: 1ffff11021d4bc10 R13: ffff88810ea5e000 R14: ffff88810ea5e020 R15: ffff88810ea5e084 FS: 0000000000000000(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f8a9bfdc1e0 CR3: 000000010bb34000 CR4: 00000000003526b0 Call Trace: NF_HOOK include/linux/netfilter.h:317 [inline] br_forward_finish net/bridge/br_forward.c:66 [inline] NF_HOOK include/linux/netfilter.h:317 [inline] __br_forward+0x25c/0x390 net/bridge/br_forward.c:115 deliver_clone net/bridge/br_forward.c:131 [inline] maybe_deliver net/bridge/br_forward.c:191 [inline] br_flood+0x50e/0x730 net/bridge/br_forward.c:237 br_handle_frame_finish+0x12f9/0x1760 net/bridge/br_input.c:215 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+0xfae/0x3ab0 net/core/dev.c:5657 __netif_receive_skb_one_core net/core/dev.c:5761 [inline] __netif_receive_skb net/core/dev.c:5876 [inline] process_backlog+0x3e5/0xad0 net/core/dev.c:6212 __napi_poll+0xd3/0x610 net/core/dev.c:6863 napi_poll net/core/dev.c:6932 [inline] net_rx_action+0x5ea/0xd80 net/core/dev.c:7054 handle_softirqs+0x1aa/0x630 kernel/softirq.c:621 run_ksoftirqd+0x20/0x30 kernel/softirq.c:999 smpboot_thread_fn+0x48f/0x8b0 kernel/smpboot.c:164 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 net_ratelimit: 90252 callbacks suppressed ICMPv6: NA: aa:aa:aa:aa:aa:1c advertised our address fe80::a8aa:aaff:feaa:aa1c on veth1_to_bridge! ICMPv6: NA: aa:aa:aa:aa:aa:1c advertised our address fe80::1c on veth1_to_bridge! ICMPv6: NA: aa:aa:aa:aa:aa:1c advertised our address fe80::a8aa:aaff:feaa:aa1c on veth1_to_bridge! ICMPv6: NA: aa:aa:aa:aa:aa:1c advertised our address fe80::1c on veth1_to_bridge! ICMPv6: NA: aa:aa:aa:aa:aa:1c advertised our address fe80::a8aa:aaff:feaa:aa1c on veth1_to_bridge! ICMPv6: NA: aa:aa:aa:aa:aa:1c advertised our address fe80::1c on veth1_to_bridge! ICMPv6: NA: aa:aa:aa:aa:aa:1c advertised our address fe80::a8aa:aaff:feaa:aa1c on veth1_to_bridge! ICMPv6: NA: aa:aa:aa:aa:aa:1c advertised our address fe80::1c on veth1_to_bridge! ICMPv6: NA: aa:aa:aa:aa:aa:1c advertised our address fe80::a8aa:aaff:feaa:aa1c on veth1_to_bridge! ICMPv6: NA: aa:aa:aa:aa:aa:1c advertised our address fe80::1c on veth1_to_bridge!