rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (1 GPs behind) idle=bfbc/1/0x4000000000000000 softirq=20981/20982 fqs=2
rcu: 	(detected by 0, t=10502 jiffies, g=13349, q=229 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 7457 Comm: syz.2.384 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:check_preemption_disabled+0x47/0x120
Code: 07 65 8b 0d bb 5e 26 07 f7 c1 ff ff ff 7f 74 23 65 48 8b 0d 9b 5e 26 07 48 3b 4c 24 08 0f 85 cc 00 00 00 48 83 c4 10 5b 41 5e <41> 5f 5d e9 81 ca 02 00 cc 48 c7 04 24 00 00 00 00 9c 8f 04 24 f7
RSP: 0018:ffffc900001e07c8 EFLAGS: 00000086
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 7bdea119966b8300
RDX: 0000000000000000 RSI: ffffffff8d9cdcbc RDI: ffffffff8be33e00
RBP: ffffffff81ada78b R08: 0000000000000001 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed1026cc4f51 R12: 0000000000000000
R13: ffff888136627a98 R14: 0000000000000001 R15: 0000000000000046
FS:  00007f87276f36c0(0000) GS:ffff8881a3c13000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000106ae0000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 lock_acquire+0xe7/0x360
 _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:get_unused_fd_flags+0x57/0x80
Code: 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 be c1 e6 ff 41 bf f0 03 00 00 4d 03 3e 4c 89 f8 48 c1 e8 03 42 80 3c 20 00 <74> 08 4c 89 ff e8 9f c1 e6 ff 49 8b 37 31 ff 89 da 5b 41 5c 41 5e
RSP: 0018:ffffc90004e2fe30 EFLAGS: 00000246
RAX: 1ffff110213d4cbe RBX: 0000000000000000 RCX: 0000000000080000
RDX: ffffc90008039000 RSI: 0000000000000015 RDI: 0000000000000016
RBP: ffffc90004e2ff48 R08: ffffffff8fa3a837 R09: 1ffffffff1f47506
R10: dffffc0000000000 R11: fffffbfff1f47507 R12: dffffc0000000000
R13: 0000200000000040 R14: ffff88802761c2a0 R15: ffff888109ea65f0
 __sys_socketpair+0x67/0x560
 __x64_sys_socketpair+0x9b/0xb0
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f872678eba9
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:00007f87276f3038 EFLAGS: 00000246 ORIG_RAX: 0000000000000035
RAX: ffffffffffffffda RBX: 00007f87269d5fa0 RCX: 00007f872678eba9
RDX: 0000000000000000 RSI: 0000000000000005 RDI: 0000000000000001
RBP: 00007f8726811e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000200000000040 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f87269d6038 R14: 00007f87269d5fa0 R15: 00007ffe6fd8bab8
 </TASK>
rcu: rcu_preempt kthread starved for 10498 jiffies! g13349 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: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>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 28 Comm: kworker/u9:1 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
Workqueue: events_unbound toggle_allocation_gate
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:ffffc9000061f660 EFLAGS: 00000293
RAX: ffffffff81b4621b RBX: 1ffff11026cc7f61 RCX: ffff88801caf9cc0
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc9000061f7e0 R08: ffffffff8fa3a837 R09: 1ffffffff1f47506
R10: dffffc0000000000 R11: fffffbfff1f47507 R12: ffff88813663fb08
R13: dffffc0000000000 R14: ffff88804b03b1c0 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff8880b8613000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f87276d1fc8 CR3: 000000000df36000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <TASK>
 on_each_cpu_cond_mask+0x3f/0x80
 smp_text_poke_batch_finish+0x5f9/0x1130
 arch_jump_label_transform_apply+0x1c/0x30
 static_key_enable_cpuslocked+0x128/0x250
 static_key_enable+0x1a/0x20
 toggle_allocation_gate+0xad/0x240
 process_scheduled_works+0xae1/0x17b0
 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x439/0x7d0
 ret_from_fork_asm+0x1a/0x30
 </TASK>
