syzbot

rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-....: (10500 ticks this GP) idle=2ce/1/0x4000000000000002 softirq=196932/196941 fqs=5249 
rcu: 	 (t=10502 jiffies g=240301 q=6250)
NMI backtrace for cpu 0
CPU: 0 PID: 27072 Comm: syz-executor.3 Not tainted 5.1.0-rc4+ #62
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x172/0x1f0 lib/dump_stack.c:113
 nmi_cpu_backtrace.cold+0x63/0xa4 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x1be/0x236 lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
 rcu_dump_cpu_stacks+0x183/0x1cf kernel/rcu/tree.c:1223
 print_cpu_stall kernel/rcu/tree.c:1360 [inline]
 check_cpu_stall kernel/rcu/tree.c:1434 [inline]
 rcu_pending kernel/rcu/tree.c:3103 [inline]
 rcu_sched_clock_irq.cold+0x500/0xa4a kernel/rcu/tree.c:2544
 update_process_times+0x32/0x80 kernel/time/timer.c:1635
 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:161
 tick_sched_timer+0x47/0x130 kernel/time/tick-sched.c:1271
 __run_hrtimer kernel/time/hrtimer.c:1389 [inline]
 __hrtimer_run_queues+0x33e/0xde0 kernel/time/hrtimer.c:1451
 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1509
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1035 [inline]
 smp_apic_timer_interrupt+0x120/0x570 arch/x86/kernel/apic/apic.c:1060
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807
 </IRQ>
RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:767 [inline]
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0x95/0xe0 kernel/locking/spinlock.c:184
Code: 48 c7 c0 70 96 92 88 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 75 39 48 83 3d 12 d5 81 01 00 74 24 48 89 df 57 9d <0f> 1f 44 00 00 bf 01 00 00 00 e8 4c 1a 3d fa 65 8b 05 15 2c f1 78
RSP: 0018:ffff88805c5477f0 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13
RAX: 1ffffffff11252ce RBX: 0000000000000282 RCX: 1ffff11014050541
RDX: dffffc0000000000 RSI: ffff8880a02829e8 RDI: 0000000000000282
RBP: ffff88805c547800 R08: ffff8880a0282140 R09: ffff8880a0282a08
R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff8a6ef9a8
R13: 0000000000000282 R14: ffffffff8a6ef9a8 R15: 0000000000000000
 __debug_check_no_obj_freed lib/debugobjects.c:798 [inline]
 debug_check_no_obj_freed+0x200/0x464 lib/debugobjects.c:817
 free_pages_prepare mm/page_alloc.c:1129 [inline]
 free_pcp_prepare mm/page_alloc.c:1143 [inline]
 free_unref_page_prepare mm/page_alloc.c:2888 [inline]
 free_unref_page+0x1f1/0x600 mm/page_alloc.c:2937
 free_the_page mm/page_alloc.c:4662 [inline]
 __free_pages mm/page_alloc.c:4670 [inline]
 __free_pages+0x72/0xb0 mm/page_alloc.c:4667
 relay_destroy_buf+0x12d/0x360 kernel/relay.c:215
 relay_open_buf.part.0+0x839/0xb60 kernel/relay.c:481
 relay_open_buf kernel/relay.c:449 [inline]
 relay_open kernel/relay.c:599 [inline]
 relay_open+0x523/0x980 kernel/relay.c:563
 do_blk_trace_setup+0x414/0xb90 kernel/trace/blktrace.c:532
 __blk_trace_setup+0xe3/0x190 kernel/trace/blktrace.c:577
 blk_trace_setup+0x4f/0x70 kernel/trace/blktrace.c:595
 sg_ioctl+0x6a2/0x2b20 drivers/scsi/sg.c:1117
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:509 [inline]
 do_vfs_ioctl+0xd6e/0x1390 fs/ioctl.c:696
 ksys_ioctl+0xab/0xd0 fs/ioctl.c:713
 __do_sys_ioctl fs/ioctl.c:720 [inline]
 __se_sys_ioctl fs/ioctl.c:718 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718
 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4582f9
Code: ad b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 7b b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ff8ae669c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000004582f9
RDX: 0000000020000000 RSI: 00000000c0481273 RDI: 0000000000000006
RBP: 000000000073bfa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ff8ae66a6d4
R13: 00000000004bf702 R14: 00000000004d1548 R15: 00000000ffffffff