rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (0 ticks this GP) idle=d834/1/0x4000000000000000 softirq=405759/405759 fqs=0
rcu: 	(detected by 1, t=10506 jiffies, g=287701, q=231 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 5291 Comm: kworker/0:3 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:  0x0 (rcu_gp)
RIP: 0010:mm_get_cid+0xab/0x130
Code: 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc 49 c7 c5 c8 24 c6 8d 49 c1 ed 03 bd 00 00 00 80 eb 07 44 89 f0 f7 d8 71 d4 f3 90 <43> 0f b6 44 25 00 84 c0 75 41 44 8b 3d 6c bf 32 0c 48 89 df 4c 89
RSP: 0018:ffffc90007097a08 EFLAGS: 00000887
RAX: 0000000080000000 RBX: ffff8881bd7f97d0 RCX: dffffc0000000000
RDX: 0000000000000002 RSI: 0000000000000002 RDI: ffff8881bd7f97d0
RBP: 0000000080000000 R08: ffff8881bd7f9653 R09: 1ffff11037aff2ca
R10: dffffc0000000000 R11: ffffed1037aff2cb R12: dffffc0000000000
R13: 1ffffffff1b8c499 R14: 0000000080000000 R15: 0000000000000002
FS:  0000000000000000(0000) GS:ffff88818e40f000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f097a25a658 CR3: 00000001754da000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000002000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __schedule+0x21ae/0x4fb0
 schedule+0x164/0x360
 worker_thread+0xa81/0xd90
 kthread+0x726/0x8b0
 ret_from_fork+0x51b/0xa40
 ret_from_fork_asm+0x1a/0x30
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10505 jiffies! g287701 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=100334
rcu: rcu_preempt kthread starved for 10506 jiffies! g287701 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27336 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 __schedule+0x14ef/0x4fb0
 schedule+0x164/0x360
 schedule_timeout+0x158/0x2c0
 rcu_gp_fqs_loop+0x312/0x1560
 rcu_gp_kthread+0x9d/0x3b0
 kthread+0x726/0x8b0
 ret_from_fork+0x51b/0xa40
 ret_from_fork_asm+0x1a/0x30
 </TASK>
