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BUG: KASAN: stack-out-of-bounds in unwind_next_frame+0x131a/0x1700 arch/x86/kernel/unwind_orc.c:474
Read of size 8 at addr ffff8880921c7aa0 by task syz-executor945/29363

CPU: 1 PID: 29363 Comm: syz-executor945 Not tainted 4.14.184-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x1b2/0x283 lib/dump_stack.c:58
 print_address_description.cold+0x54/0x1dc mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report mm/kasan/report.c:409 [inline]
 kasan_report.cold+0xa9/0x2b9 mm/kasan/report.c:393
 unwind_next_frame+0x131a/0x1700 arch/x86/kernel/unwind_orc.c:474
 perf_callchain_kernel+0x38c/0x520 arch/x86/events/core.c:2343
 get_perf_callchain+0x2df/0x740 kernel/events/callchain.c:217
 perf_callchain+0x147/0x190 kernel/events/callchain.c:190
 perf_prepare_sample+0x75b/0x1350 kernel/events/core.c:6157
 __perf_event_output kernel/events/core.c:6273 [inline]
 perf_event_output_forward+0xc9/0x1f0 kernel/events/core.c:6291
 __perf_event_overflow+0x113/0x310 kernel/events/core.c:7536
 perf_swevent_hrtimer+0x220/0x350 kernel/events/core.c:8746
 __run_hrtimer kernel/time/hrtimer.c:1223 [inline]
 __hrtimer_run_queues+0x24b/0xb90 kernel/time/hrtimer.c:1287
 hrtimer_interrupt+0x1e6/0x5e0 kernel/time/hrtimer.c:1321
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1075 [inline]
 smp_apic_timer_interrupt+0x117/0x5f0 arch/x86/kernel/apic/apic.c:1100
 apic_timer_interrupt+0x93/0xa0 arch/x86/entry/entry_64.S:793
 </IRQ>
RIP: 0010:arch_local_save_flags arch/x86/include/asm/paravirt.h:774 [inline]
RIP: 0010:arch_local_irq_save arch/x86/include/asm/paravirt.h:796 [inline]
RIP: 0010:lock_acquire+0x97/0x3f0 kernel/locking/lockdep.c:3993
RSP: 0018:ffff8880921c7930 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff10
RAX: 1ffffffff0f62cd0 RBX: ffff888088baa2c0 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: ffff888088baab44
RBP: ffffffff87bfa460 R08: 0000000000000001 R09: 0000000000000000
R10: ffff8880921c7b08 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000001
 pcpu_alloc+0x86f/0xf70 mm/percpu.c:1380
 retint_kernel+0x2d/0x2d
RIP: 0000:pcpu_alloc+0x86f/0xf70 mm/percpu.c:1380
RSP: 14000c0:ffff88807c9f0958 EFLAGS: 000001c0 ORIG_RAX: ffffffff8176ab0f
RAX: 00000000000001bf RBX: 0000000000000000 RCX: 0000000000000010
RDX: 0000000000000040 RSI: ffff88807c9f0958 RDI: 00000000014000c0
RBP: ffffffff814646b8 R08: ffff8880921c7b08 R09: 0000000000000000
R10: ffffffff81003d3b R11: ffff8880921c7b08 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000

The buggy address belongs to the page:
page:ffffea00024871c0 count:0 mapcount:0 mapping:          (null) index:0x0
flags: 0xfffe0000000000()
raw: 00fffe0000000000 0000000000000000 0000000000000000 00000000ffffffff
raw: 0000000000000000 0000000100000001 0000000000000000 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880921c7980: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8880921c7a00: f1 f1 f1 f1 00 00 00 f2 00 00 00 f2 f2 f2 00 00
>ffff8880921c7a80: 00 00 00 f3 f3 f3 f3 f3 00 00 00 00 00 00 00 00
                               ^
 ffff8880921c7b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1
 ffff8880921c7b80: f1 f1 f1 f1 04 f2 04 f3 f3 f3 00 00 00 00 00 00
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