rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (0 ticks this GP) idle=304c/1/0x4000000000000000 softirq=65274/65274 fqs=0
rcu: 	(detected by 0, t=10506 jiffies, g=54753, q=373 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 19236 Comm: syz.0.2632 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:__kasan_check_write+0xf/0x20
Code: 66 66 2e 0f 1f 84 00 00 00 00 00 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 ba 01 00 00 00 <e9> bc e4 ff ff 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90
RSP: 0018:ffffc900001e0b38 EFLAGS: 00000056
RAX: 00000000ffffff01 RBX: ffffffff99d93a90 RCX: ffffffff819dffe1
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffc900001e0b80
RBP: ffffc900001e0bf0 R08: ffffffff99d93a93 R09: 1ffffffff33b2752
R10: dffffc0000000000 R11: fffffbfff33b2753 R12: ffffffff99d93aa0
R13: ffffffff99d93a98 R14: 1ffffffff33b2754 R15: 1ffffffff33b2753
FS:  0000555572f5e500(0000) GS:ffff8881a3c1b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000001580 CR3: 00000000326de000 CR4: 00000000000006f0
Call Trace:
 <IRQ>
 do_raw_spin_lock+0x121/0x290
 _raw_spin_lock_irqsave+0xb3/0xf0
 debug_object_deactivate+0x9a/0x250
 debug_deactivate+0x1d/0x200
 __hrtimer_run_queues+0x2b0/0xc60
 hrtimer_interrupt+0x45b/0xaa0
 __sysvec_apic_timer_interrupt+0x10b/0x410
 sysvec_apic_timer_interrupt+0xa1/0xc0
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20
RIP: 0010:mt_validate+0x2485/0x4380
Code: 04 24 4a 8d 3c 20 48 89 f8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 80 3c 08 00 74 05 e8 d3 d4 b0 f6 48 8b 04 24 49 8b 04 04 <48> 89 44 24 60 e8 d1 3c 07 00 41 89 c4 31 ff 89 c6 e8 55 6d 4d f6
RSP: 0018:ffffc90007a474a0 EFLAGS: 00000246
RAX: ffff888113385980 RBX: ffffffff8cbb0161 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: ffffffff8f8a5100 RDI: ffff8880264b8280
RBP: ffffc90007a47670 R08: ffff88802c4d3980 R09: 0000000000000004
R10: 0000000000000003 R11: 0000000000000000 R12: ffff8880264b8280
R13: 0000000000000000 R14: 00007f7795ff7fff R15: ffff888110d20040
 validate_mm+0xb6/0x4b0
 mmap_region+0x15a5/0x20c0
 do_mmap+0xc45/0x10d0
 vm_mmap_pgoff+0x2a6/0x4d0
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f779758ec23
Code: f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 41 89 ca 41 f7 c1 ff 0f 00 00 75 14 b8 09 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 25 c3 0f 1f 40 00 48 c7 c0 a8 ff ff ff 64 c7
RSP: 002b:00007ffcd7874cb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007f7795ff76c0 RCX: 00007f779758ec23
RDX: 0000000000000000 RSI: 0000000000021000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 00000000ffffffff R09: 0000000000000000
R10: 0000000000020022 R11: 0000000000000246 R12: 00007ffcd7874e10
R13: ffffffffffffffc0 R14: 0000000000001000 R15: 0000000000000000
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10505 jiffies! g54753 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=1 timer-softirq=23638
rcu: rcu_preempt kthread starved for 10506 jiffies! g54753 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:27496 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>
vkms_vblank_simulate: vblank timer overrun
