rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-....: (1 GPs behind) idle=5394/1/0x4000000000000000 softirq=27030/27031 fqs=4778
rcu: 	         hardirqs   softirqs   csw/system
rcu: 	 number:  1288089          0            0
rcu: 	cputime:     7835      44644           33   ==> 52480(ms)
rcu: 	(t=10500 jiffies g=21929 q=2715 ncpus=2)
rcu: rcu_preempt kthread starved for 919 jiffies! g21929 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt     state:R  running task     stack:27304 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 __schedule+0x1821/0x5740
 schedule+0x164/0x360
 schedule_timeout+0x158/0x2c0
 rcu_gp_fqs_loop+0x312/0x11d0
 rcu_gp_kthread+0x9e/0x2b0
 kthread+0x388/0x470
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 13 Comm: kworker/u8:1 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Workqueue: netns cleanup_net
RIP: 0010:__kasan_check_read+0x0/0x20
Code: 21 8e 48 89 de e8 40 a8 f6 fe 31 ed eb cf cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <f3> 0f 1e fa 89 f6 48 8b 0c 24 31 d2 e9 8f e5 ff ff 66 66 66 66 66
RSP: 0018:ffffc90000127358 EFLAGS: 00000202
RAX: 0000000000000001 RBX: ffffffff8e6149b8 RCX: ffffffff8bab7b72
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffffff8e6149b8
RBP: ffffc90000127450 R08: ffffffff8e6149bb R09: 1ffffffff1cc2937
R10: dffffc0000000000 R11: fffffbfff1cc2938 R12: 1ffff92000024e74
R13: 0000000000000001 R14: ffffc900001273c0 R15: 1ffffffff1cc2937
FS:  0000000000000000(0000) GS:ffff88818dc89000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0a3f830d3a CR3: 000000000e74a000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <TASK>
 native_queued_spin_lock_slowpath+0xc2/0x960
 do_raw_spin_lock+0x26c/0x2f0
 mntput_no_expire_slowpath+0x106/0xbd0
 __simple_recursive_removal+0x215/0x520
 debugfs_remove+0x5b/0x70
 nsim_dev_reload_destroy+0x72/0x490
 nsim_dev_reload_down+0x8a/0xc0
 devlink_reload+0x1eb/0x8c0
 devlink_pernet_pre_exit+0x1ff/0x420
 ops_undo_list+0x187/0x940
 cleanup_net+0x56b/0x800
 process_scheduled_works+0xb5d/0x1860
 worker_thread+0xa53/0xfc0
 kthread+0x388/0x470
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>
CPU: 1 UID: 0 PID: 7980 Comm: syz.0.623 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:ip6_mtu+0x1ee/0x490
Code: 85 ed 0f 84 c4 00 00 00 e8 8f 5e 6e f7 4d 85 ff 74 25 e8 85 5e 6e f7 49 81 c7 e0 05 00 00 4c 89 f8 48 c1 e8 03 42 0f b6 04 20 <84> c0 0f 85 77 02 00 00 41 8b 2f eb 0a e8 60 5e 6e f7 bd 00 05 00
RSP: 0018:ffffc90000a088f0 EFLAGS: 00000a02
RAX: 0000000000000000 RBX: ffff888176abb680 RCX: ffff88811d47d880
RDX: 0000000000000100 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000001 R08: ffffffff8a57618d R09: ffffffff8e95cd60
R10: 0000000000000003 R11: 0000000000000100 R12: dffffc0000000000
R13: ffff888176abb6a0 R14: ffffffff8a57618d R15: ffff88811ef415e0
FS:  00007f3871df66c0(0000) GS:ffff8882a9289000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3871dd5d58 CR3: 000000011d5fc000 CR4: 00000000000006f0
DR0: 0000200000000300 DR1: 0000200000000300 DR2: 0000200000000300
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 ip6_finish_output+0x136/0x480
 ip6_output+0x340/0x550
 ndisc_send_skb+0xd0b/0x1670
 addrconf_rs_timer+0x395/0x6d0
 call_timer_fn+0x192/0x5e0
 __run_timer_base+0x652/0x8b0
 run_timer_softirq+0xb7/0x170
 handle_softirqs+0x22a/0x840
 __irq_exit_rcu+0xca/0x220
 irq_exit_rcu+0x9/0x30
 sysvec_apic_timer_interrupt+0xa6/0xc0
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20
RIP: 0010:perf_trace_lock+0xd5/0x410
Code: 42 80 3c 20 00 74 08 48 89 df e8 c6 03 90 00 48 8b 03 48 85 c0 48 c7 c7 00 db cc 8b 48 0f 45 f8 48 89 7c 24 28 e8 8b 69 03 0a <49> 89 c5 49 8d 5e 60 48 89 d8 48 c1 e8 03 42 80 3c 20 00 74 08 48
RSP: 0018:ffffc90008b079e0 EFLAGS: 00000246
RAX: 000000000000000a RBX: ffffffff8e6149e8 RCX: 000000008bde8302
RDX: ffffffff824e0b74 RSI: ffffffff8e6149d0 RDI: ffffffff8bde8320
RBP: ffffc90008b07ad0 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52001160f5c R12: dffffc0000000000
R13: ffffffff824e0b74 R14: ffffffff8e828de0 R15: 1ffff92001160f44
 lock_release+0x38e/0x3c0
 _raw_spin_unlock+0x16/0x50
 get_mountpoint+0x254/0x510
 attach_recursive_mnt+0x236/0x24e0
 do_loopback+0x367/0x6c0
 __se_sys_mount+0x31d/0x420
 do_syscall_64+0x15f/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3873b9cdd9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f3871df6028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f3873e16090 RCX: 00007f3873b9cdd9
RDX: 0000000000000000 RSI: 0000200000000200 RDI: 0000200000000000
RBP: 00007f3873c32d69 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000008b7840 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3873e16128 R14: 00007f3873e16090 R15: 00007ffdc6fc8708
 </TASK>
sched: DL replenish lagged too much
