rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (0 ticks this GP) idle=9434/1/0x4000000000000000 softirq=34903/34903 fqs=3
rcu: 	(detected by 0, t=10502 jiffies, g=28401, q=407 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 10130 Comm: syz.0.1182 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:do_raw_spin_lock+0x12e/0x290
Code: 00 48 89 df be 04 00 00 00 e8 0e d4 85 00 48 8d 7c 24 40 be 04 00 00 00 e8 ff d3 85 00 8b 44 24 40 b9 01 00 00 00 f0 0f b1 0b <0f> 85 dd 00 00 00 65 8b 1d 29 d7 02 11 48 b9 00 00 00 00 00 fc ff
RSP: 0018:ffffc900001e07c0 EFLAGS: 00000046
RAX: 0000000000000000 RBX: ffff888136627a80 RCX: 0000000000000001
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffc900001e0800
RBP: ffffc900001e0870 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff5200003c100 R12: ffff888136627a90
R13: ffff888136627a88 R14: 1ffff11026cc4f52 R15: 1ffff11026cc4f51
FS:  00007f68ff60c6c0(0000) GS:ffff8881a3c11000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c24a13c CR3: 000000011181c000 CR4: 00000000000006f0
DR0: 0000200000000300 DR1: 0000200000000300 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 _raw_spin_lock_irqsave+0xb3/0xf0
 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:deref_stack_reg+0x1b3/0x230
Code: 39 f0 0f 96 c0 20 c8 3c 01 75 30 4c 89 c7 49 89 f7 e8 11 08 00 00 49 89 c6 48 8b 5c 24 18 48 89 d8 48 c1 e8 03 42 80 3c 38 00 <74> 08 48 89 df e8 83 f2 b0 00 4c 89 33 b0 01 eb 02 31 c0 48 83 c4
RSP: 0018:ffffc90006eb6c20 EFLAGS: 00000246
RAX: 1ffff92000dd6db1 RBX: ffffc90006eb6d88 RCX: 0000000000000001
RDX: ffffc90006eb6d88 RSI: dffffc0000000000 RDI: ffffc90006eb7ee0
RBP: 1ffff92000dd6da9 R08: ffffc90006eb7ee0 R09: 0000000000000000
R10: ffffc90006eb6d98 R11: fffff52000dd6db5 R12: 1ffff92000dd6daa
R13: 1ffff92000dd6dab R14: ffffc90006eb7f48 R15: dffffc0000000000
 unwind_next_frame+0x17c4/0x2390
 arch_stack_walk+0x11c/0x150
 stack_trace_save+0x9c/0xe0
 kasan_save_track+0x3e/0x80
 __kasan_slab_alloc+0x6c/0x80
 kmem_cache_alloc_noprof+0x1c1/0x3c0
 _request_firmware+0x6be/0x15b0
 request_firmware+0x36/0x50
 reg_reload_regdb+0x8f/0x480
 genl_family_rcv_msg_doit+0x215/0x300
 genl_rcv_msg+0x60e/0x790
 netlink_rcv_skb+0x208/0x470
 genl_rcv+0x28/0x40
 netlink_unicast+0x82f/0x9e0
 netlink_sendmsg+0x805/0xb30
 __sock_sendmsg+0x21c/0x270
 ____sys_sendmsg+0x505/0x830
 ___sys_sendmsg+0x21f/0x2a0
 __x64_sys_sendmsg+0x19b/0x260
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f68fe78ec29
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:00007f68ff60c038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f68fe9d5fa0 RCX: 00007f68fe78ec29
RDX: 0000000000000000 RSI: 0000200000000080 RDI: 0000000000000009
RBP: 00007f68fe811e41 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f68fe9d6038 R14: 00007f68fe9d5fa0 R15: 00007ffc48254388
 </TASK>
rcu: rcu_preempt kthread starved for 10496 jiffies! g28401 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:26376 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: 10129 Comm: syz.0.1182 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+0xd38/0x12d0
Code: 89 ee 83 e6 01 31 ff e8 b6 63 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 61 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 45 5f 0b 00 eb e4 44
RSP: 0000:ffffc90006e57720 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 1ffff11026cc7f61 RCX: ffff888107855640
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90006e578a0 R08: ffffffff8fa3b537 R09: 1ffffffff1f476a6
R10: dffffc0000000000 R11: fffffbfff1f476a7 R12: ffff88813663fb08
R13: dffffc0000000000 R14: ffff88804b03b1c0 R15: 0000000000000001
FS:  000055557a3a5500(0000) GS:ffff8880b8611000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f68ff50d680 CR3: 000000011181c000 CR4: 00000000000006f0
DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
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: 0033:0x7f68fe745e4e
Code: 31 ff 4d 01 f2 41 0f 92 c7 72 a6 48 8b 44 24 08 48 8d 84 06 00 08 00 00 4c 01 f0 48 21 d8 49 39 c2 72 8e 31 c0 be 01 00 00 00 <f0> 0f b1 35 2a 78 dc 00 0f 85 26 0a 00 00 c1 e1 02 48 8b 05 3a 78
RSP: 002b:00007ffc48254330 EFLAGS: 00010246
RAX: 0000000000000000 RBX: fffffffffffff000 RCX: 0000000000000006
RDX: 000000000000003f RSI: 0000000000000001 RDI: 00007ffc48254478
RBP: 0000000000000000 R08: 0000000000000018 R09: 0000000000000032
R10: 0000000000021000 R11: 0000000000020000 R12: 00007ffc48254480
R13: ffffffffffffffc0 R14: 0000000000001000 R15: 0000000000000000
 </TASK>
