INFO: task syz.6.7884:24593 blocked for more than 123 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.7884      state:D stack:0     pid:24593 tgid:24592 ppid:19428  flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5945 [inline]
 __schedule+0x1322/0x1df0 kernel/sched/core.c:7791
 __schedule_loop kernel/sched/core.c:7872 [inline]
 schedule+0xc6/0x240 kernel/sched/core.c:7887
 synchronize_rcu_expedited+0x6b0/0x7b0 kernel/rcu/tree_exp.h:991
 namespace_unlock+0x1ec/0x3d0 fs/namespace.c:1700
 drop_collected_mounts fs/namespace.c:2228 [inline]
 put_mnt_ns+0xad/0xf0 fs/namespace.c:5596
 free_nsproxy+0x52/0x290 kernel/nsproxy.c:193
 put_nsproxy include/linux/nsproxy.h:118 [inline]
 switch_task_namespaces kernel/nsproxy.c:251 [inline]
 exit_task_namespaces+0x99/0xe0 kernel/nsproxy.c:256
 do_exit+0x9b7/0x2630 kernel/exit.c:952
 do_group_exit+0x22a/0x300 kernel/exit.c:1095
 get_signal+0x139d/0x14f0 kernel/signal.c:2933
 arch_do_signal_or_restart+0x96/0x720 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+0x58/0xb0 kernel/entry/common.c:218
 do_syscall_64+0x64/0xf0 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7ffbfd18f6c9
RSP: 002b:00007ffbfdff20e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: 0000000000000001 RBX: 00007ffbfd3e5fa8 RCX: 00007ffbfd18f6c9
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007ffbfd3e5fac
RBP: 00007ffbfd3e5fa0 R08: 7fffffffffffffff R09: 0000000000000000
R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffbfd3e6038 R14: 00007ffe5903fcb0 R15: 00007ffe5903fd98
 </TASK>
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 0b5ffdee5fcd2f7749818d1ff954e9c21353764e
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
 <TASK>
 __dump_stack+0x21/0x30 lib/dump_stack.c:94
 dump_stack_lvl+0x10c/0x190 lib/dump_stack.c:120
 dump_stack+0x19/0x20 lib/dump_stack.c:129
 nmi_cpu_backtrace+0x2bf/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+0xd8f/0xed0 kernel/hung_task.c:423
 kthread+0x2ca/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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 20 Comm: rcuop/0 Not tainted syzkaller #0 0b5ffdee5fcd2f7749818d1ff954e9c21353764e
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:246 [inline]
RIP: 0010:__sanitizer_cov_trace_const_cmp4+0x2c/0x90 kernel/kcov.c:314
Code: 1e fa 55 48 89 e5 48 8b 45 08 65 48 8b 14 25 00 eb 04 00 65 8b 0d fc e7 7e 7e 81 e1 00 01 ff 00 74 11 81 f9 00 01 00 00 75 5b <83> ba ec 0b 00 00 00 74 52 8b 8a c8 0b 00 00 83 f9 03 75 47 48 8b
RSP: 0018:ffffc900000071e8 EFLAGS: 00000246
RAX: ffffffff84e85cd5 RBX: 0000000000000000 RCX: 0000000000000100
RDX: ffff888103663900 RSI: 00000000fffffffd RDI: 00000000ffffffff
RBP: ffffc900000071e8 R08: ffffc90000007540 R09: ffffc90000007550
R10: ffffc900000076b0 R11: fffff52000000eda R12: 0000000000000001
R13: 1ffff1102570a518 R14: 0000000000000003 R15: 00000000fffffffd
FS:  0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007efe23cb8b68 CR3: 0000000110c82000 CR4: 00000000003526b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 find_match+0x185/0x10f0 net/ipv6/route.c:787
 __find_rr_leaf+0x23c/0x790 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+0x2c5/0x9b0 net/ipv6/route.c:2230
 ip6_pol_route+0x167/0x12c0 net/ipv6/route.c:2266
 ip6_pol_route_input+0x5a/0x80 net/ipv6/route.c:2323
 pol_lookup_func include/net/ip6_fib.h:626 [inline]
 fib6_rule_lookup+0x4cc/0x6b0 net/ipv6/fib6_rules.c:117
 ip6_route_input_lookup net/ipv6/route.c:2335 [inline]
 ip6_route_input+0x59f/0x8d0 net/ipv6/route.c:2631
 ip6_rcv_finish_core net/ipv6/ip6_input.c:66 [inline]
 ip6_rcv_finish+0x15a/0x3e0 net/ipv6/ip6_input.c:77
 NF_HOOK include/linux/netfilter.h:317 [inline]
 ipv6_rcv+0xed/0x220 net/ipv6/ip6_input.c:309
 __netif_receive_skb_one_core net/core/dev.c:5769 [inline]
 __netif_receive_skb net/core/dev.c:5882 [inline]
 process_backlog+0x44b/0xae0 net/core/dev.c:6218
 __napi_poll+0xd3/0x610 net/core/dev.c:6869
 napi_poll net/core/dev.c:6938 [inline]
 net_rx_action+0x584/0xce0 net/core/dev.c:7060
 handle_softirqs+0x1ab/0x630 kernel/softirq.c:621
 __do_softirq+0xf/0x16 kernel/softirq.c:659
 do_softirq+0xa6/0x100 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+0x5c6/0xd20 kernel/rcu/tree.c:2594
 nocb_cb_wait kernel/rcu/tree_nocb.h:923 [inline]
 rcu_nocb_cb_kthread+0x4dc/0xac0 kernel/rcu/tree_nocb.h:957
 kthread+0x2ca/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>