rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-....: (10540 ticks this GP) idle=9d34/1/0x4000000000000000 softirq=0/0 fqs=5044 rcuc=10538 jiffies(starved)
rcu: 	         hardirqs   softirqs   csw/system
rcu: 	 number:     8585         78          272
rcu: 	cputime:      193         36        52258   ==> 52490(ms)
rcu: 	(t=10500 jiffies g=27969 q=7741 ncpus=2)
CPU: 1 UID: 0 PID: 9616 Comm: syz.4.1519 Tainted: G             L      syzkaller #0 PREEMPT_{RT,(full)} 
Tainted: [L]=SOFTLOCKUP
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+0x47/0x80
Code: f7 e8 4d 12 75 f6 f7 c3 00 02 00 00 74 05 e8 90 ed a0 f6 9c 58 a9 00 02 00 00 75 27 f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> a4 9f 67 f6 65 8b 05 cd ff 43 07 85 c0 74 18 5b 41 5e c3 cc cc
RSP: 0018:ffffc9000546fc38 EFLAGS: 00000206
RAX: 0000000000000002 RBX: 0000000000000246 RCX: 0000000080000001
RDX: 0000000000000006 RSI: ffffffff8d626ff0 RDI: 0000000000000001
RBP: 00000000ffffffff R08: ffffffff8f8acbf7 R09: 1ffffffff1f1597e
R10: dffffc0000000000 R11: fffffbfff1f1597f R12: ffff88816ce48880
R13: ffff88823c628700 R14: ffff88823c6283c0 R15: 1ffff110478c50e0
FS:  00007ff6a374d6c0(0000) GS:ffff8882a9f1f000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd5753c5000 CR3: 0000000105364000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 hrtimer_try_to_cancel+0x499/0x670
 rtc_irq_set_freq+0xb3/0x340
 rtc_dev_ioctl+0x814/0xef0
 __se_sys_ioctl+0xff/0x170
 do_syscall_64+0x15f/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff6a551cdd9
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:00007ff6a374d028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007ff6a5796090 RCX: 00007ff6a551cdd9
RDX: 0000000000000005 RSI: 000000004008700c RDI: 0000000000000007
RBP: 00007ff6a55b2d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff6a5796128 R14: 00007ff6a5796090 R15: 00007ffd0b970858
 </TASK>
