rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (0 ticks this GP) idle=18a4/1/0x4000000000000000 softirq=50506/50506 fqs=0
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P12118/1:b..l
rcu: 	(detected by 1, t=10502 jiffies, g=41861, q=238 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 12110 Comm: syz.2.1836 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:_raw_spin_unlock_irqrestore+0x98/0x110
Code: 1d f6 4c 89 f7 e8 88 be 1d f6 f7 c3 00 02 00 00 74 05 e8 5b 1a 47 f6 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f6 44 24 21 02 <75> 4f f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 e8 43 b5 0f f6 65
RSP: 0018:ffffc90000007880 EFLAGS: 00000046
RAX: 1ffffffff1c35187 RBX: 0000000000000802 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff88804b027ac0
RBP: ffffc90000007918 R08: ffff88804b027ac3 R09: 1ffff11009604f58
R10: dffffc0000000000 R11: ffffed1009604f59 R12: dffffc0000000000
R13: ffff88804b027b40 R14: ffff88804b027ac0 R15: 1ffff92000000f10
FS:  00007f0016bfe6c0(0000) GS:ffff8880b8403000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0016bbbfc8 CR3: 00000000442d0000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 hrtimer_try_to_cancel+0x3be/0x420
 hrtimer_cancel+0x3b/0x50
 cpu_clock_event_stop+0xd9/0x130
 __perf_event_overflow+0x580/0xe40
 perf_swevent_hrtimer+0x3b8/0x500
 __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:rcu_is_watching+0x70/0xb0
Code: c3 d8 ff c2 92 49 03 1e 48 89 d8 48 c1 e8 03 42 0f b6 04 38 84 c0 75 34 8b 03 65 ff 0d 69 d8 1a 11 74 11 83 e0 04 c1 e8 02 5b <41> 5e 41 5f e9 c7 3c da 09 cc e8 81 e0 8c ff eb e8 48 c7 c7 40 30
RSP: 0018:ffffc90002bb7358 EFLAGS: 00000202
RAX: 0000000000000001 RBX: 1ffffd40000962e9 RCX: 8ce0953cba4b4700
RDX: ffff888105dcba00 RSI: ffffffff8c03d4c0 RDI: ffffffff8c03d480
RBP: 0000000000000001 R08: 0000000000000000 R09: ffffffff8230adc7
R10: dffffc0000000000 R11: ffffed100371bbac R12: 0000000000000000
R13: ffffea00004b1740 R14: ffffffff8ddc4dd0 R15: dffffc0000000000
 page_table_check_clear+0x1c1/0x700
 unmap_page_range+0x3415/0x4370
 unmap_vmas+0x399/0x580
 exit_mmap+0x240/0xb40
 __mmput+0x118/0x430
 copy_process+0x293a/0x3c20
 kernel_clone+0x21e/0x840
 __x64_sys_clone+0x185/0x1e0
 do_syscall_64+0xfa/0xfa0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0015d8ec29
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:00007f0016bfdfe8 EFLAGS: 00000202 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007f0015fd5fa0 RCX: 00007f0015d8ec29
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000008044080
RBP: 00007f0015e11e41 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 00007f0015fd6038 R14: 00007f0015fd5fa0 R15: 00007ffea5a3f3a8
 </TASK>
task:syz.7.1839      state:R  running task     stack:26088 pid:12118 tgid:12117 ppid:10325  task_flags:0x40054c flags:0x00080000
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 preempt_schedule_common+0x83/0xd0
 preempt_schedule+0xae/0xc0
 preempt_schedule_thunk+0x16/0x30
 _raw_spin_unlock+0x3f/0x50
 unmap_page_range+0x3a7f/0x4370
 unmap_vmas+0x399/0x580
 exit_mmap+0x240/0xb40
 __mmput+0x118/0x430
 exit_mm+0x1da/0x2c0
 do_exit+0x648/0x2300
 do_group_exit+0x21c/0x2d0
 get_signal+0x1285/0x1340
 arch_do_signal_or_restart+0xa0/0x790
 exit_to_user_mode_loop+0x72/0x130
 do_syscall_64+0x2bd/0xfa0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f46f438ec29
RSP: 002b:00007f46f521a0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007f46f45d5fa8 RCX: 00007f46f438ec29
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f46f45d5fa8
RBP: 00007f46f45d5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f46f45d6038 R14: 00007ffdf3a649f0 R15: 00007ffdf3a64ad8
 </TASK>
rcu: rcu_preempt kthread starved for 10502 jiffies! g41861 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R  running task     stack:26696 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
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+0x4bc/0x870
 ret_from_fork_asm+0x1a/0x30
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 UID: 0 PID: 12109 Comm: syz.2.1836 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:smp_call_function_many_cond+0xd33/0x12d0
Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 26 73 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 d1 6e 0b 00 eb 38 f3 90 <42> 0f b6 04 2b 84 c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 b5 6e
RSP: 0000:ffffc900033f7700 EFLAGS: 00000293
RAX: ffffffff81b4e79b RBX: 1ffff11009608441 RCX: ffff88801fd83a00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900033f7880 R08: ffffffff8fc34277 R09: 1ffffffff1f8684e
R10: dffffc0000000000 R11: fffffbfff1f8684f R12: ffff88804b042208
R13: dffffc0000000000 R14: ffff88813663b200 R15: 0000000000000000
FS:  0000555555b5c500(0000) GS:ffff8881a3a03000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0016b0576e CR3: 00000000442d0000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <TASK>
 on_each_cpu_cond_mask+0x3f/0x80
 flush_tlb_mm_range+0x6b1/0x12d0
 ptep_clear_flush+0x120/0x170
 do_wp_page+0x1bc2/0x5800
 __handle_mm_fault+0x1033/0x5400
 handle_mm_fault+0x40a/0x8e0
 do_user_addr_fault+0xa7c/0x1380
 exc_page_fault+0x82/0x100
 asm_exc_page_fault+0x26/0x30
RIP: 0033:0x7f0015c6ebc4
Code: 48 83 ec 38 80 7f 4e 00 44 8b 6f 48 88 4c 24 1f 0f 85 c5 03 00 00 45 85 ed 0f 85 b7 03 00 00 4c 8b 52 38 49 89 d0 4c 03 52 18 <c6> 47 4e 01 8b 52 04 48 89 fb 48 89 d0 49 8d 14 d2 49 39 50 28 0f
RSP: 002b:00007ffea5a3f3e0 EFLAGS: 00010202
RAX: 00007f0015fd6180 RBX: 00007f0016b05720 RCX: 0000000000000000
RDX: 00007f0015fd6218 RSI: 0000000000000007 RDI: 00007f0016b05720
RBP: 00007f0015fd6218 R08: 00007f0015fd6218 R09: 0000000000000000
R10: 00007f0014ffb008 R11: 0000000000000000 R12: 00000000fffffc03
R13: 0000000000000000 R14: 00007ffea5a3f4c8 R15: 00007ffea5a3f620
 </TASK>
