rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	(detected by 1, t=10502 jiffies, g=86349, q=354 ncpus=2)
rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4294993091-4294982589), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g86349 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x200
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=30514
rcu: rcu_preempt kthread starved for 10502 jiffies! g86349 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x200 ->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 stack:27536 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 __schedule+0x17b4/0x5680
 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: 18580 Comm: syz.5.5441 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:sched_mm_cid_fork+0x64b/0x10e0
Code: 0f b6 04 28 84 c0 0f 85 a6 09 00 00 c7 03 00 00 00 40 e9 19 01 00 00 49 c7 c4 b8 7e 26 8e 49 c1 ec 03 41 bd 00 00 00 80 eb 0a <89> e8 f7 d8 0f 81 09 fe ff ff f3 90 48 b8 00 00 00 00 00 fc ff df
RSP: 0018:ffffc900042b7c48 EFLAGS: 00000046
RAX: 0000000000000002 RBX: ffff8881ba7497d0 RCX: 0000000080000001
RDX: dffffc0000000000 RSI: 0000000000000002 RDI: ffff8881ba7497d0
RBP: 0000000080000000 R08: 1ffff110374e91a9 R09: 0000000000000000
R10: ffff8881ba748e8c R11: fffff52000856f78 R12: 1ffffffff1c4cfd7
R13: 0000000080000000 R14: 0000000000000002 R15: ffff8881ba748c40
FS:  00007f308f6816c0(0000) GS:ffff88818dc93000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b34119ff8 CR3: 00000001bde50000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <TASK>
 bprm_execve+0xdb7/0x1440
 do_execveat_common+0x50d/0x690
 __x64_sys_execveat+0xc7/0xf0
 do_syscall_64+0x15f/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f308e79cdd9
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:00007f308f681028 EFLAGS: 00000246 ORIG_RAX: 0000000000000142
RAX: ffffffffffffffda RBX: 00007f308ea15fa0 RCX: 00007f308e79cdd9
RDX: 0000000000000000 RSI: 0000200000000000 RDI: 0000000000000004
RBP: 00007f308e832d69 R08: 0000000000001000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f308ea16038 R14: 00007f308ea15fa0 R15: 00007ffcc477a288
 </TASK>
