syzbot

INFO: task syz.4.586:2226 blocked for more than 122 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.586       state:D stack:0     pid:2226  tgid:2223  ppid:1578   flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:6027 [inline]
 __schedule+0x14ce/0x2100 kernel/sched/core.c:7894
 __schedule_loop kernel/sched/core.c:7975 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7990
 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
 rcu_barrier+0x415/0x540 kernel/rcu/tree.c:4657
 netdev_run_todo+0x118/0xce0 net/core/dev.c:10912
 rtnl_unlock net/core/rtnetlink.c:152 [inline]
 rtnetlink_rcv_msg+0x903/0xa40 net/core/rtnetlink.c:6679
 netlink_rcv_skb+0x259/0x4f0 net/netlink/af_netlink.c:2545
 rtnetlink_rcv+0x20/0x30 net/core/rtnetlink.c:6696
 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_sendmsg+0x9e1/0xa30 net/socket.c:2609
 ___sys_sendmsg+0x2a6/0x370 net/socket.c:2663
 __sys_sendmsg net/socket.c:2692 [inline]
 __do_sys_sendmsg net/socket.c:2701 [inline]
 __se_sys_sendmsg net/socket.c:2699 [inline]
 __x64_sys_sendmsg+0x1fb/0x2d0 net/socket.c:2699
 x64_sys_call+0x2a4c/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:47
 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: 0033:0x7fe64199ce59
RSP: 002b:00007fe64289d028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fe641c15fa0 RCX: 00007fe64199ce59
RDX: 0000000000000000 RSI: 0000200000000740 RDI: 0000000000000004
RBP: 00007fe641a32d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe641c16038 R14: 00007fe641c15fa0 R15: 00007fffa7316448
 </TASK>
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 471281939cd7bfdfff4c6b6074d5d68627c837ba
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
 <TASK>
 __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
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 33 Comm: rcuop/1 Not tainted syzkaller #0 471281939cd7bfdfff4c6b6074d5d68627c837ba
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:find_match+0x48/0x10e0 net/ipv6/route.c:778
Code: 41 89 ce 89 55 b0 41 89 f4 48 89 fb 49 bf 00 00 00 00 00 fc ff df e8 c7 54 87 fc 48 89 5d d0 48 83 c3 17 48 89 d8 48 c1 e8 03 <42> 0f b6 04 38 84 c0 0f 85 9a 0c 00 00 44 0f b6 3b 44 89 fe 83 e6
RSP: 0018:ffffc9000022fc38 EFLAGS: 00000a07
RAX: 1ffff11021c6c69a RBX: ffff88810e3634d7 RCX: ffff88810367df00
RDX: 0000000000000100 RSI: 0000000000000001 RDI: ffff88810e3634c0
RBP: ffffc9000022fcf0 R08: ffffc9000022ff80 R09: ffffc9000022ff90
R10: ffffc900002300f0 R11: fffff52000046022 R12: 0000000000000001
R13: ffffc9000022ff80 R14: 0000000000000003 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f59e4985fc0 CR3: 00000000074aa000 CR4: 00000000003526b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 __find_rr_leaf+0x24e/0x840 net/ipv6/route.c:869
 find_rr_leaf net/ipv6/route.c:890 [inline]
 rt6_select net/ipv6/route.c:934 [inline]
 fib6_table_lookup+0x2ee/0x9e0 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:645 [inline]
 fib6_rule_lookup+0x4ee/0x6d0 net/ipv6/fib6_rules.c:117
 ip6_route_input_lookup net/ipv6/route.c:2347 [inline]
 ip6_route_input+0x62e/0x8f0 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+0x147/0x7b0 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+0x120c/0x17a0 net/bridge/br_input.c:221
 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:5695
 __netif_receive_skb_one_core net/core/dev.c:5799 [inline]
 __netif_receive_skb net/core/dev.c:5914 [inline]
 process_backlog+0x3e5/0xad0 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
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x74/0x80 kernel/softirq.c:430
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 rcu_do_batch+0x5d9/0xd40 kernel/rcu/tree.c:2594
 nocb_cb_wait kernel/rcu/tree_nocb.h:923 [inline]
 rcu_nocb_cb_kthread+0x524/0xb30 kernel/rcu/tree_nocb.h:957
 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
 </TASK>
net_ratelimit: 138996 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:fe:f0:e9:a4:9b:54, 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:fe:f0:e9:a4:9b:54, 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:fe:f0:e9:a4:9b:54, vlan:0)