rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-...!: (1 GPs behind) idle=757c/1/0x4000000000000000 softirq=13172/13173 fqs=0
rcu: 	(t=29916 jiffies g=9309 q=263 ncpus=2)
rcu: rcu_preempt kthread starved for 29916 jiffies! g9309 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:27544 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 __schedule+0x1821/0x5740
 schedule+0x164/0x360
 schedule_timeout+0x158/0x2c0
 rcu_gp_fqs_loop+0x312/0x11d0
 rcu_gp_kthread+0x9e/0x2b0
 kthread+0x388/0x470
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 10 Comm: kworker/0:1 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 request_firmware_work_func
RIP: 0010:__lock_acquire+0x1839/0x2cf0
Code: 0d 3b a0 14 4d 85 e4 0f 84 b2 01 00 00 49 8b 44 24 10 48 85 c0 0f 84 1c 0d 00 00 8b 0d f8 3a a0 14 39 48 5c 0f 84 67 ff ff ff <89> 48 5c 49 8b 44 24 30 48 85 c0 74 25 41 0f b6 4c 24 2a 89 ca 80
RSP: 0018:ffffc900000f7448 EFLAGS: 00000083
RAX: ffffffff93e55a20 RBX: 00000000000003fd RCX: 00000000000148c0
RDX: ffffffff96d45a48 RSI: ffff888102e8b108 RDI: 00000000000003fd
RBP: 733f0c21a9dff68d R08: ffffc900000f7410 R09: 0000000000000020
R10: 0000000000000003 R11: ffffffff81a21f90 R12: ffffffff96cae758
R13: ffff888102e8b108 R14: ffff888102e8a500 R15: 000000000000005d
FS:  0000000000000000(0000) GS:ffff88818dc8d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa2dbd52866 CR3: 000000016be8a000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 lock_acquire+0x106/0x350
 seqcount_lockdep_reader_access+0x55/0x100
 ktime_expiry_to_cycles+0x4e/0x1e0
 clockevents_program_event+0x199/0x630
 __hrtimer_rearm_deferred+0x270/0x450
 irqentry_exit+0x6d5/0x760
 asm_sysvec_apic_timer_interrupt+0x1a/0x20
RIP: 0010:vprintk_emit+0x45d/0x560
Code: 0f 84 44 ff ff ff e8 92 29 21 00 fb eb 44 e8 8a 29 21 00 e8 d5 2c 04 0a 4d 85 f6 74 94 e8 7b 29 21 00 fb 48 c7 c7 a0 f1 94 8e <31> f6 ba 01 00 00 00 31 c9 41 b8 01 00 00 00 45 31 c9 53 e8 cb 18
RSP: 0018:ffffc900000f78a0 EFLAGS: 00000293
RAX: ffffffff81a49855 RBX: ffffffff81a496cf RCX: ffff888102e8a500
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8e94f1a0
RBP: ffffc900000f7950 R08: ffffffff9030b6f7 R09: 1ffffffff20616de
R10: dffffc0000000000 R11: fffffbfff20616df R12: 0000000000000000
R13: 0000000000000026 R14: 0000000000000200 R15: 1ffff9200001ef18
 _printk+0xdd/0x130
 regdb_fw_cb+0x19c/0x1c0
 request_firmware_work_func+0x105/0x1c0
 process_scheduled_works+0xb5d/0x1860
 worker_thread+0xa53/0xfc0
 kthread+0x388/0x470
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>
CPU: 1 UID: 0 PID: 5743 Comm: syz.1.8 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:vcpu_run+0x5a02/0x7860
Code: 4c 8b a4 24 28 01 00 00 4c 89 e3 48 c1 eb 03 42 0f b6 04 3b 84 c0 0f 85 1c 0b 00 00 41 c6 04 24 01 e8 02 eb 85 00 fb 4c 89 f0 <48> c1 e8 03 42 80 3c 38 00 74 08 4c 89 f7 e8 2b fd e8 00 49 ff 06
RSP: 0018:ffffc9000481f5e0 EFLAGS: 00000202
RAX: ffff8881695dc720 RBX: 1ffff1102d2bb6bf RCX: 0000000080000001
RDX: 0000000000000006 RSI: ffffffff8dfa6837 RDI: ffffffff8c28af60
RBP: ffffc9000481f9b0 R08: ffffffff9030b6f7 R09: 1ffffffff20616de
R10: dffffc0000000000 R11: fffffbfff20616df R12: ffff8881695db5fa
R13: ffff8881695da9c0 R14: ffff8881695dc720 R15: dffffc0000000000
FS:  00007f8705cfa6c0(0000) GS:ffff8882a928d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000017516e000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 kvm_arch_vcpu_ioctl_run+0x11e6/0x20d0
 kvm_vcpu_ioctl+0xa62/0xfd0
 __se_sys_ioctl+0xfc/0x170
 do_syscall_64+0x15f/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8704d9cdd9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f8705cfa028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f8705015fa0 RCX: 00007f8704d9cdd9
RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000005
RBP: 00007f8704e32d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8705016038 R14: 00007f8705015fa0 R15: 00007ffddfbc9288
 </TASK>
