rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (1 GPs behind) idle=e4f4/1/0x4000000000000000 softirq=15374/15376 fqs=56
rcu: 	(detected by 0, t=10505 jiffies, g=8285, q=190 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 6004 Comm: syz.0.27 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:hrtimer_try_to_cancel+0x3a4/0x420
Code: 00 bd 01 00 00 00 4c 8b 64 24 08 48 8b 44 24 10 42 80 3c 30 00 74 08 4c 89 e7 e8 f7 95 75 00 49 8b 1c 24 48 89 d8 48 c1 e8 03 <42> 80 3c 30 00 74 08 48 89 df e8 dd 95 75 00 48 8b 3b 4c 89 fe e8
RSP: 0018:ffffc900001e0928 EFLAGS: 00000806
RAX: 1ffff11026cc4f60 RBX: ffff888136627b00 RCX: ffff888108061cc0
RDX: 0000000000010000 RSI: 0000000000000004 RDI: ffffc900001e0800
RBP: 00000000ffffffff R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff5200003c100 R12: ffff88803a1cdf58
R13: ffff888136627b00 R14: dffffc0000000000 R15: 0000000000000802
FS:  00007f55cac5f6c0(0000) GS:ffff8881a3c13000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b32b23ffc CR3: 0000000029a40000 CR4: 00000000000006f0
Call Trace:
 <IRQ>
 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:should_fail_ex+0x44/0x560
Code: fb 49 bc 00 00 00 00 00 fc ff df 65 8b 05 d4 14 a3 0d a9 00 01 ff 00 0f 84 ee 00 00 00 49 89 dd 49 c1 ed 03 43 80 7c 25 00 00 <74> 08 48 89 df e8 72 83 25 fd 48 83 3b 00 0f 84 18 01 00 00 4c 8d
RSP: 0018:ffffc900030cfb30 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffffffff8e8dd060 RCX: 0000000000080000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffffffff8e8dd060
RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff820b9f10
R10: ffffc900030cfc00 R11: fffff52000619f87 R12: dffffc0000000000
R13: 1ffffffff1d1ba0c R14: 0000000000000001 R15: ffff8881080632a4
 _copy_from_user+0x2d/0xb0
 ___sys_recvmsg+0x12e/0x510
 __x64_sys_recvmsg+0x198/0x260
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f55c9d8eba9
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:00007f55cac5f038 EFLAGS: 00000246 ORIG_RAX: 000000000000002f
RAX: ffffffffffffffda RBX: 00007f55c9fd5fa0 RCX: 00007f55c9d8eba9
RDX: 0000000000000000 RSI: 0000200000000500 RDI: 0000000000000005
RBP: 00007f55c9e11e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f55c9fd6038 R14: 00007f55c9fd5fa0 R15: 00007ffd526a4138
 </TASK>
rcu: rcu_preempt kthread starved for 10225 jiffies! g8285 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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  running task     stack:27224 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>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 5861 Comm: syz-executor 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 56 63 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 01 5f 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 e5 5e
RSP: 0000:ffffc90003baf720 EFLAGS: 00000293
RAX: ffffffff81b4621b RBX: 1ffff11026cc7f61 RCX: ffff888104f13980
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90003baf8a0 R08: ffffffff8fa3a837 R09: 1ffffffff1f47506
R10: dffffc0000000000 R11: fffffbfff1f47507 R12: ffff88813663fb08
R13: dffffc0000000000 R14: ffff88804b03b1c0 R15: 0000000000000001
FS:  00005555744ac500(0000) GS:ffff8880b8613000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555744c75c8 CR3: 000000010e486000 CR4: 00000000000006f0
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+0x1033/0x5440
 handle_mm_fault+0x40a/0x8e0
 do_user_addr_fault+0xa81/0x1390
 exc_page_fault+0x76/0xf0
 asm_exc_page_fault+0x26/0x30
RIP: 0033:0x7f8550d4d02f
Code: 8d 34 19 48 39 d5 48 89 75 60 0f 95 c2 48 29 d8 48 83 c1 10 0f b6 d2 48 83 c8 01 48 c1 e2 02 48 09 da 48 83 ca 01 48 89 51 f8 <48> 89 46 08 eb 80 48 8d 0d 31 e9 0e 00 48 8d 15 35 fb 0e 00 bf 01
RSP: 002b:00007ffe3ddad1e0 EFLAGS: 00010206
RAX: 0000000000006a41 RBX: 0000000000008040 RCX: 00005555744bf590
RDX: 0000000000008041 RSI: 00005555744c75c0 RDI: 0000000000000004
RBP: 00007f8550fa7cc0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000001000 R11: 0000000000000802 R12: 0000000000008030
R13: 0000000000000076 R14: 00007f8550fa7d20 R15: 0000000000000000
 </TASK>
