rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-...!: (1 GPs behind) idle=5fcc/1/0x4000000000000000 softirq=19368/19369 fqs=44
rcu: 	(t=10500 jiffies g=10057 q=115 ncpus=2)
rcu: rcu_preempt kthread timer wakeup didn't happen for 10410 jiffies! g10057 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=1 timer-softirq=3299
rcu: rcu_preempt kthread starved for 10411 jiffies! g10057 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=1
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:I stack:26760 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_timeout+0x12b/0x270
 rcu_gp_fqs_loop+0x301/0x1540
 rcu_gp_kthread+0x99/0x390
 kthread+0x711/0x8a0
 ret_from_fork+0x3fc/0x770
 ret_from_fork_asm+0x1a/0x30
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 47 Comm: kworker/1:1 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: events ser_release
RIP: 0010:native_queued_spin_lock_slowpath+0xaf/0x8e0
Code: 00 00 00 c7 44 24 60 00 00 00 00 0f 1f 44 00 00 4c 8d 74 24 60 49 89 df 49 c1 ef 03 41 bd 01 00 00 00 eb 06 89 44 24 60 f3 90 <48> 89 df be 04 00 00 00 e8 34 f9 a6 f6 48 b8 00 00 00 00 00 fc ff
RSP: 0018:ffffc9000075f4a0 EFLAGS: 00000202
RAX: 0000000000000001 RBX: ffff88803263d540 RCX: ffffffff8b7c1dbc
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff88803263d540
RBP: ffffc9000075f598 R08: ffff88803263d543 R09: 1ffff110064c7aa8
R10: dffffc0000000000 R11: ffffed10064c7aa9 R12: 1ffff920000ebe9c
R13: 0000000000000001 R14: ffffc9000075f500 R15: 1ffff110064c7aa8
FS:  0000000000000000(0000) GS:ffff8881a3c1b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000026af0000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 queued_spin_lock_slowpath+0x43/0x50
 do_raw_spin_lock+0x21f/0x290
 dev_deactivate_many+0x2fb/0xd40
 __dev_close_many+0x162/0x6f0
 netif_close_many+0x225/0x410
 netif_close+0x158/0x210
 dev_close+0x10a/0x220
 ser_release+0x16c/0x240
 process_scheduled_works+0xae1/0x17b0
 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x3fc/0x770
 ret_from_fork_asm+0x1a/0x30
 </TASK>
CPU: 0 UID: 0 PID: 1363 Comm: aoe_tx0 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:_raw_spin_unlock_irqrestore+0xa8/0x110
Code: 74 05 e8 cb 46 4b f6 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f6 44 24 21 02 75 4f f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> 43 ef 13 f6 65 8b 05 0c 42 24 07 85 c0 74 40 48 c7 04 24 0e 36
RSP: 0018:ffffc90007db7680 EFLAGS: 00000206
RAX: fdf091ea3ad8c200 RBX: 0000000000000a02 RCX: fdf091ea3ad8c200
RDX: 0000000000000000 RSI: ffffffff8be33660 RDI: 0000000000000001
RBP: ffffc90007db7708 R08: ffffffff8fa38337 R09: 1ffffffff1f47066
R10: dffffc0000000000 R11: fffffbfff1f47067 R12: dffffc0000000000
R13: dffffc0000000000 R14: ffffffff99defee0 R15: 1ffff92000fb6ed0
FS:  0000000000000000(0000) GS:ffff8880b861b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffff51a5fe8 CR3: 0000000028a6c000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 uart_port_unlock_deref+0x111/0x2f0
 uart_write+0xc9/0x130
 handle_tx+0x23f/0x610
 dev_hard_start_xmit+0x2d7/0x830
 __dev_queue_xmit+0x1b8d/0x3b50
 tx+0x6b/0x190
 kthread+0x1d0/0x3e0
 kthread+0x711/0x8a0
 ret_from_fork+0x3fc/0x770
 ret_from_fork_asm+0x1a/0x30
 </TASK>
