INFO: task kworker/u8:10:846 blocked for more than 122 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u8:10 state:D stack:0 pid:846 tgid:846 ppid:2 flags:0x00004000 Workqueue: events_unbound linkwatch_event Call Trace: context_switch kernel/sched/core.c:6063 [inline] __schedule+0x1496/0x20b0 kernel/sched/core.c:7883 __schedule_loop kernel/sched/core.c:7960 [inline] schedule+0xc5/0x240 kernel/sched/core.c:7975 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:8032 __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 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:3273 [inline] process_scheduled_works+0x7f7/0x1060 kernel/workqueue.c:3354 worker_thread+0xc99/0x13f0 kernel/workqueue.c:3435 kthread+0x2c7/0x360 kernel/kthread.c:389 ret_from_fork+0x64/0xa0 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 b27277d6799ceeca3eb852bae8b5683c15874786 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026 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:114 nmi_trigger_cpumask_backtrace+0x142/0x2c0 lib/nmi_backtrace.c:63 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:41 cpumask_backtrace+0x1f/0x30 lib/nmi_backtrace.c:127 trigger_all_cpu_backtrace include/linux/nmi.h:160 [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+0x64/0xa0 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: 20 Comm: rcuop/0 Not tainted syzkaller #0 b27277d6799ceeca3eb852bae8b5683c15874786 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026 RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x32/0x70 kernel/kcov.c:217 Code: 48 8b 45 08 65 48 8b 0d 1c 71 7d 7e 65 8b 15 1d 71 7d 7e 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 ec 0b 00 00 00 <74> 2c 8b 91 c8 0b 00 00 83 fa 02 75 21 48 8b 91 d0 0b 00 00 48 8b RSP: 0018:ffffc90000006d10 EFLAGS: 00000246 RAX: ffffffff84fd806c RBX: 1ffff11021ef8b8c RCX: ffff888103660000 RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc90000006d10 R08: ffffc90000006f80 R09: ffffc90000006f90 R10: ffffc900000070f0 R11: fffff52000000e22 R12: 0000000000000100 R13: dffffc0000000000 R14: ffff88810f7c5c00 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fa0bbff84c0 CR3: 00000001023c2000 CR4: 00000000003526b0 Call Trace: fib6_check_expired include/net/ip6_fib.h:280 [inline] __find_rr_leaf+0x19c/0x840 net/ipv6/route.c:843 find_rr_leaf net/ipv6/route.c:890 [inline] rt6_select net/ipv6/route.c:934 [inline] fib6_table_lookup+0x2d0/0x980 net/ipv6/route.c:2242 ip6_pol_route+0x17a/0x1370 net/ipv6/route.c:2278 ip6_pol_route_input+0x5a/0x80 net/ipv6/route.c:2335 pol_lookup_func include/net/ip6_fib.h:647 [inline] fib6_rule_lookup+0x4f1/0x6d0 net/ipv6/fib6_rules.c:117 ip6_route_input_lookup net/ipv6/route.c:2347 [inline] ip6_route_input+0x60d/0x8d0 net/ipv6/route.c:2643 ip6_rcv_finish_core net/ipv6/ip6_input.c:66 [inline] ip6_rcv_finish+0x15a/0x3c0 net/ipv6/ip6_input.c:77 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+0xcd/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+0x1ad/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 local_bh_enable include/linux/bottom_half.h:33 [inline] rcu_do_batch+0x590/0xcb0 kernel/rcu/tree.c:2594 nocb_cb_wait kernel/rcu/tree_nocb.h:923 [inline] rcu_nocb_cb_kthread+0x533/0xb60 kernel/rcu/tree_nocb.h:957 kthread+0x2c7/0x360 kernel/kthread.c:389 ret_from_fork+0x64/0xa0 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 net_ratelimit: 115587 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 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:76:10:dc:fa:48:e9, 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) bridge0: received packet on veth0_to_bridge with own address as source address (addr:76:10:dc:fa:48:e9, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0) net_ratelimit: 123609 callbacks suppressed bridge0: received packet on veth0_to_bridge with own address as source address (addr:76:10:dc:fa:48:e9, 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) 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) bridge0: received packet on veth0_to_bridge with own address as source address (addr:76:10:dc:fa:48:e9, vlan:0) bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)