rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (1 GPs behind) idle=4344/1/0x4000000000000000 softirq=27012/27013 fqs=1
rcu: 	(detected by 1, t=10505 jiffies, g=17121, q=538 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 7232 Comm: syz.6.244 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+0x40/0x120
Code: 08 65 8b 05 c6 ce 25 07 65 8b 0d bb ce 25 07 f7 c1 ff ff ff 7f 74 23 65 48 8b 0d 9b ce 25 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
RSP: 0018:ffffc900000077c0 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 0000000000000802 RCX: 27f7510d0d070600
RDX: 0000000000010000 RSI: ffffffff8be33be0 RDI: ffffffff8be33ba0
RBP: ffffc90000007918 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52000000f00 R12: dffffc0000000000
R13: ffffffff81ada71e R14: ffff88804b027a98 R15: 1ffff92000000f10
FS:  00007f167f0b96c0(0000) GS:ffff8880b8613000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2d512ff8 CR3: 000000003b566000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 rcu_is_watching+0x15/0xb0
 lock_release+0x4b/0x3e0
 _raw_spin_unlock_irqrestore+0x70/0x110
 hrtimer_try_to_cancel+0x3be/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:sk_setsockopt+0x1ba6/0x2dc0
Code: e8 3f 29 66 f8 83 fb 01 0f 84 cc 07 00 00 83 fb 10 0f 84 ac 07 00 00 83 fb 1f 0f 85 fc 07 00 00 e8 9f 23 66 f8 e9 b5 07 00 00 <e8> 95 23 66 f8 8b b4 24 e0 00 00 00 48 89 df e8 56 c7 ff ff 41 89
RSP: 0018:ffffc9000174fc60 EFLAGS: 00000246
RAX: 000000000000002e RBX: ffff888110816800 RCX: 0000000000000005
RDX: ffffffff89598deb RSI: ffffffff8f520880 RDI: 000000000000003e
RBP: ffffc9000174fe48 R08: ffff888123579cc0 R09: 000000000000002e
R10: 0000000000000053 R11: 0000000000000002 R12: 1ffff920002e9f98
R13: dffffc0000000000 R14: 000000000000003e R15: 0000000000000004
 do_sock_setsockopt+0x11b/0x1b0
 __x64_sys_setsockopt+0x13f/0x1b0
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f167e18eba9
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:00007f167f0b9038 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 00007f167e3d5fa0 RCX: 00007f167e18eba9
RDX: 000000000000003e RSI: 0000000000000001 RDI: 000000000000000c
RBP: 00007f167e211e19 R08: 0000000000000004 R09: 0000000000000000
R10: 0000200000000100 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f167e3d6038 R14: 00007f167e3d5fa0 R15: 00007ffc2d3b8d78
 </TASK>
rcu: rcu_preempt kthread starved for 10500 jiffies! g17121 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:26568 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: 1 UID: 0 PID: 32 Comm: rcu_tasks_trace 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:its_return_thunk+0x0/0x10
Code: cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc <c3> cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 e9 6b a2 b5 f5 cc
RSP: 0018:ffffc9000065f878 EFLAGS: 00000293
RAX: ffffffff81b4481a RBX: ffff88813663b240 RCX: ffff888100e8b980
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc9000065f980 R08: ffffffff8fa38f37 R09: 1ffffffff1f471e6
R10: dffffc0000000000 R11: fffffbfff1f471e7 R12: 1ffff11026cc7649
R13: dffffc0000000000 R14: 1ffff920000cbf14 R15: ffff88813663b248
FS:  0000000000000000(0000) GS:ffff8881a3c13000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2d51cff8 CR3: 000000001fe7a000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <TASK>
 smp_call_function_single+0x28a/0x590
 trc_wait_for_one_reader+0x445/0x6d0
 check_all_holdout_tasks_trace+0x174/0xc30
 rcu_tasks_wait_gp+0x7b4/0xac0
 rcu_tasks_one_gp+0xc19/0xdf0
 rcu_tasks_kthread+0x195/0x1c0
 kthread+0x711/0x8a0
 ret_from_fork+0x439/0x7d0
 ret_from_fork_asm+0x1a/0x30
 </TASK>
