rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (0 ticks this GP) idle=f694/1/0x4000000000000000 softirq=408432/408432 fqs=0
rcu: 	(detected by 1, t=10506 jiffies, g=272853, q=434 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 16 Comm: rcu_preempt 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:_find_first_zero_bit+0x25/0xb0
Code: 90 90 90 90 90 f3 0f 1e fa 41 57 41 56 41 55 41 54 53 48 85 f6 74 46 48 89 f3 49 89 fe 49 bc 00 00 00 00 00 fc ff df 48 89 f8 <48> c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 08 6a 92 fd 49 8b 06
RSP: 0018:ffffc90000157798 EFLAGS: 00000002
RAX: ffff88816d30f9d0 RBX: 0000000000000002 RCX: dffffc0000000000
RDX: 0000000000000002 RSI: 0000000000000002 RDI: ffff88816d30f9d0
RBP: 0000000080000000 R08: ffff88816d30f853 R09: 1ffff1102da61f0a
R10: dffffc0000000000 R11: ffffed102da61f0b R12: dffffc0000000000
R13: 1ffffffff1bafa99 R14: ffff88816d30f9d0 R15: 0000000000000002
FS:  0000000000000000(0000) GS:ffff88818e329000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000113012000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 mm_get_cid+0xc7/0x130
 __schedule+0x21b0/0x4fb0
 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>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10505 jiffies! g272853 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=86059
rcu: rcu_preempt kthread starved for 10506 jiffies! g272853 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:27512 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 </TASK>
