syzbot

INFO: task syz-executor.5:19154 blocked for more than 143 seconds.
      Not tainted 5.9.0-rc1-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.5  state:D stack:28768 pid:19154 ppid:  6899 flags:0x00004004
Call Trace:
 context_switch kernel/sched/core.c:3778 [inline]
 __schedule+0x8e5/0x21e0 kernel/sched/core.c:4527
 schedule+0xd0/0x2a0 kernel/sched/core.c:4602
 schedule_timeout+0x1d8/0x250 kernel/time/timer.c:1855
 do_wait_for_common kernel/sched/completion.c:85 [inline]
 __wait_for_common kernel/sched/completion.c:106 [inline]
 wait_for_common kernel/sched/completion.c:117 [inline]
 wait_for_completion+0x163/0x260 kernel/sched/completion.c:138
 flush_workqueue+0x3ff/0x13e0 kernel/workqueue.c:2832
 rxrpc_destroy_all_connections+0xf9/0x3ff net/rxrpc/conn_object.c:470
 rxrpc_exit_net+0x1ac/0x2f0 net/rxrpc/net_ns.c:122
 ops_exit_list+0xb0/0x160 net/core/net_namespace.c:186
 setup_net+0x502/0x850 net/core/net_namespace.c:364
 copy_net_ns+0x2cf/0x5e0 net/core/net_namespace.c:482
 create_new_namespaces+0x3f6/0xb10 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0xbd/0x1f0 kernel/nsproxy.c:231
 ksys_unshare+0x445/0x8e0 kernel/fork.c:2921
 __do_sys_unshare kernel/fork.c:2989 [inline]
 __se_sys_unshare kernel/fork.c:2987 [inline]
 __x64_sys_unshare+0x2d/0x40 kernel/fork.c:2987
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45d5b9
Code: Bad RIP value.
RSP: 002b:00007f59fbf8cc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 0000000000036480 RCX: 000000000045d5b9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000040000000
RBP: 000000000118d150 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118d12c
R13: 00007ffd0e4f9fcf R14: 00007f59fbf8d9c0 R15: 000000000118d12c

Showing all locks held in the system:
1 lock held by khungtaskd/1168:
 #0: ffffffff89bd6900 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5825
3 locks held by kworker/1:2/2505:
1 lock held by in:imklog/6568:
 #0: ffff88809f0f6bb0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:930
2 locks held by kworker/u4:8/12804:
1 lock held by syz-executor.2/19108:
 #0: ffffffff8a7da670 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x2ac/0x5e0 net/core/net_namespace.c:478
1 lock held by syz-executor.2/19150:
 #0: ffffffff8a7da670 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x2ac/0x5e0 net/core/net_namespace.c:478
1 lock held by syz-executor.5/19149:
 #0: ffffffff8a7da670 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x2ac/0x5e0 net/core/net_namespace.c:478
1 lock held by syz-executor.5/19154:
 #0: ffffffff8a7da670 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x2ac/0x5e0 net/core/net_namespace.c:478

=============================================

NMI backtrace for cpu 0
CPU: 0 PID: 1168 Comm: khungtaskd Not tainted 5.9.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x18f/0x20d lib/dump_stack.c:118
 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x1b3/0x223 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:209 [inline]
 watchdog+0xd7d/0x1000 kernel/hung_task.c:295
 kthread+0x3b5/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 16 Comm: ksoftirqd/1 Not tainted 5.9.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__find_rr_leaf+0x303/0xd10 net/ipv6/route.c:810
Code: e8 82 ce 86 fa 48 8d bb 80 00 00 00 48 89 f8 48 c1 e8 03 0f b6 04 28 84 c0 74 08 3c 03 0f 8e d2 07 00 00 44 8b a3 80 00 00 00 <44> 8b 74 24 10 44 89 e7 44 89 f6 e8 4d ca 86 fa 45 39 f4 0f 85 fa
RSP: 0018:ffffc90000d7f4f0 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffff88808cae5e00 RCX: ffffffff86ed717a
RDX: ffff8880a9686440 RSI: ffffffff86ed708e RDI: ffff88808cae5e80
RBP: dffffc0000000000 R08: 0000000000000001 R09: ffffc90000d7f6c0
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000100
R13: ffffc90000d7f7d8 R14: 0000000000000000 R15: ffff88804a9b0ea0
FS:  0000000000000000(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0fac02ead0 CR3: 000000002c409000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 find_rr_leaf net/ipv6/route.c:862 [inline]
 rt6_select net/ipv6/route.c:906 [inline]
 fib6_table_lookup+0x5b3/0xa20 net/ipv6/route.c:2193
 ip6_pol_route+0x1e1/0x1190 net/ipv6/route.c:2229
 pol_lookup_func include/net/ip6_fib.h:583 [inline]
 fib6_rule_lookup+0x111/0x6f0 net/ipv6/fib6_rules.c:115
 ip6_route_input_lookup net/ipv6/route.c:2299 [inline]
 ip6_route_input+0x68a/0xae0 net/ipv6/route.c:2468
 ip6_rcv_finish_core.constprop.0.isra.0+0x168/0x570 net/ipv6/ip6_input.c:63
 ip6_rcv_finish net/ipv6/ip6_input.c:74 [inline]
 NF_HOOK include/linux/netfilter.h:301 [inline]
 NF_HOOK include/linux/netfilter.h:295 [inline]
 ipv6_rcv+0x22b/0x3c0 net/ipv6/ip6_input.c:307
 __netif_receive_skb_one_core+0x114/0x180 net/core/dev.c:5286
 __netif_receive_skb+0x27/0x1c0 net/core/dev.c:5400
 process_backlog+0x28d/0x7f0 net/core/dev.c:6242
 napi_poll net/core/dev.c:6688 [inline]
 net_rx_action+0x4a1/0xe80 net/core/dev.c:6758
 __do_softirq+0x2de/0xa24 kernel/softirq.c:298
 run_ksoftirqd kernel/softirq.c:652 [inline]
 run_ksoftirqd+0x89/0x100 kernel/softirq.c:644
 smpboot_thread_fn+0x655/0x9e0 kernel/smpboot.c:165
 kthread+0x3b5/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294