rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (0 ticks this GP) idle=dad4/1/0x4000000000000000 softirq=15766/15766 fqs=0
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P6213/1:b..l
rcu: 	(detected by 0, t=10506 jiffies, g=8837, q=237 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 6216 Comm: syz.2.85 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:mark_lock+0x26/0x190
Code: 90 90 90 90 55 41 57 41 56 41 55 41 54 53 8b 46 20 89 c1 81 e1 00 00 03 00 83 f9 01 bb 09 00 00 00 83 db 00 83 fa 08 0f 45 da <bd> 01 00 00 00 89 d9 d3 e5 25 ff 1f 00 00 48 0f a3 05 c4 0f 0b 12
RSP: 0018:ffffc900001e0718 EFLAGS: 00000093
RAX: 00000000000c4067 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffff88810830c470 RDI: ffff88810830b980
RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff81adabcb
R10: dffffc0000000000 R11: ffffed1026cc4f51 R12: ffffffffffffff02
R13: 0000000000000002 R14: ffff88810830c470 R15: 0000000000000000
FS:  00007f8e870776c0(0000) GS:ffff8881a3c11000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000000011c0 CR3: 0000000116654000 CR4: 00000000000006f0
Call Trace:
 <IRQ>
 __lock_acquire+0x65a/0xd20
 lock_acquire+0x120/0x360
 _raw_spin_lock_irqsave+0xa7/0xf0
 hrtimer_try_to_cancel+0x22b/0x420
 hrtimer_cancel+0x3b/0x50
 cpu_clock_event_stop+0xd9/0x130
 __perf_event_overflow+0x580/0xe40
 perf_swevent_hrtimer+0x3c5/0x550
 __hrtimer_run_queues+0x4e0/0xc60
 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:finish_task_switch+0x26b/0x950
Code: 0f 84 3c 01 00 00 48 85 db 0f 85 63 01 00 00 0f 1f 44 00 00 4c 8b 75 d0 4c 89 e7 e8 9f 80 ec 09 e8 ea 41 36 00 fb 4c 8b 65 c0 <49> 8d bc 24 18 16 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 28 84 c0
RSP: 0018:ffffc9000682f758 EFLAGS: 00000282
RAX: dc706d7cfc945b00 RBX: 0000000000000000 RCX: dc706d7cfc945b00
RDX: 0000000000000000 RSI: ffffffff8d9baef1 RDI: ffffffff8be34480
RBP: ffffc9000682f7b0 R08: ffffffff8fa3b537 R09: 1ffffffff1f476a6
R10: dffffc0000000000 R11: fffffbfff1f476a7 R12: ffff88810830b980
R13: dffffc0000000000 R14: ffff888108309cc0 R15: ffff88813663ab58
 __schedule+0x17a0/0x4cc0
 schedule+0x165/0x360
 __futex_wait+0x1c3/0x3e0
 futex_wait+0x104/0x360
 do_futex+0x333/0x420
 __se_sys_futex+0x36f/0x400
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8e8618ec29
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f8e870770e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 00007f8e863d6098 RCX: 00007f8e8618ec29
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f8e863d6098
RBP: 00007f8e863d6090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8e863d6128 R14: 00007ffdecf08000 R15: 00007ffdecf080e8
 </TASK>
task:syz.1.82        state:R  running task     stack:27384 pid:6213  tgid:6213  ppid:6206   task_flags:0x40004c flags:0x00004000
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 preempt_schedule_notrace+0xd1/0x110
 preempt_schedule_notrace_thunk+0x16/0x30
 lock_release+0x3ca/0x3e0
 unwind_next_frame+0x19a9/0x2390
 __unwind_start+0x5b9/0x760
 arch_stack_walk+0xe4/0x150
 stack_trace_save+0x9c/0xe0
 kasan_save_track+0x3e/0x80
 kasan_save_free_info+0x46/0x50
 __kasan_slab_free+0x5b/0x80
 kmem_cache_free+0x18f/0x400
 unlink_anon_vmas+0x614/0x670
 free_pgtables+0x72b/0x9c0
 exit_mmap+0x444/0xb50
 __mmput+0x118/0x430
 exit_mm+0x1da/0x2c0
 do_exit+0x648/0x2300
 __x64_sys_exit+0x40/0x40
 x64_sys_call+0x21da/0x2200
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f95f058ec29
RSP: 002b:00007f95f1431fe8 EFLAGS: 00000246 ORIG_RAX: 000000000000003c
RAX: ffffffffffffffda RBX: 00007f95f07d5fa0 RCX: 00007f95f058ec29
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f95f0611e41 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f95f07d6038 R14: 00007f95f07d5fa0 R15: 00007ffc2de23cd8
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10505 jiffies! g8837 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=1 timer-softirq=3789
rcu: rcu_preempt kthread starved for 10506 jiffies! g8837 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:27160 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+0x439/0x7d0
 ret_from_fork_asm+0x1a/0x30
 </TASK>
