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BUG: KASAN: stack-out-of-bounds in __read_once_size include/linux/compiler.h:182 [inline]
BUG: KASAN: stack-out-of-bounds in update_stack_state+0x63b/0x690 arch/x86/kernel/unwind_frame.c:270
Read of size 8 at addr ffff88018c43e958 by task syz-executor3/19072

CPU: 0 PID: 19072 Comm: syz-executor3 Not tainted 4.20.0-rc1+ #86
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x244/0x39d lib/dump_stack.c:113
 print_address_description.cold.7+0x9/0x1ff mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report.cold.8+0x242/0x309 mm/kasan/report.c:412
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
 __read_once_size include/linux/compiler.h:182 [inline]
 update_stack_state+0x63b/0x690 arch/x86/kernel/unwind_frame.c:270
 __unwind_start+0xfe/0x340 arch/x86/kernel/unwind_frame.c:404
 unwind_start arch/x86/include/asm/unwind.h:54 [inline]
 perf_callchain_kernel+0x2b3/0x650 arch/x86/events/core.c:2381
 get_perf_callchain+0x538/0xbf0 kernel/events/callchain.c:202
 perf_callchain+0x171/0x1c0 kernel/events/core.c:6364
 perf_prepare_sample+0x93a/0x1770 kernel/events/core.c:6391
 __perf_event_output kernel/events/core.c:6506 [inline]
 perf_event_output_forward+0x110/0x2d0 kernel/events/core.c:6524
 __perf_event_overflow+0x239/0x4c0 kernel/events/core.c:7768
 perf_swevent_overflow+0xad/0x150 kernel/events/core.c:7844
 perf_swevent_event+0x1f0/0x2e0 kernel/events/core.c:7877
 do_perf_sw_event kernel/events/core.c:7985 [inline]
 ___perf_sw_event+0x4a9/0x7c0 kernel/events/core.c:8016
 perf_sw_event_sched include/linux/perf_event.h:1071 [inline]
 perf_event_task_sched_out include/linux/perf_event.h:1109 [inline]
 prepare_task_switch kernel/sched/core.c:2615 [inline]
 context_switch kernel/sched/core.c:2796 [inline]
 __schedule+0x11a3/0x21d0 kernel/sched/core.c:3472
 schedule+0xfe/0x460 kernel/sched/core.c:3516
 freezable_schedule include/linux/freezer.h:172 [inline]
 futex_wait_queue_me+0x3f9/0x840 kernel/futex.c:2530
 futex_wait+0x45c/0xa50 kernel/futex.c:2645
 do_futex+0x31a/0x26d0 kernel/futex.c:3528
 __do_sys_futex kernel/futex.c:3589 [inline]
 __se_sys_futex kernel/futex.c:3557 [inline]
 __x64_sys_futex+0x472/0x6a0 kernel/futex.c:3557
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457569
Code: fd b3 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 cb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f2eb95f9cf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 000000000072bf08 RCX: 0000000000457569
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000072bf08
RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000072bf0c
R13: 00007ffe18f0ea3f R14: 00007f2eb95fa9c0 R15: 0000000000000000

The buggy address belongs to the page:
page:ffffea0006310f80 count:0 mapcount:0 mapping:0000000000000000 index:0xffff88018c43fb40
flags: 0x2fffc0000000000()
raw: 02fffc0000000000 dead000000000100 dead000000000200 0000000000000000
raw: ffff88018c43fb40 ffff88018c43e040 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88018c43e800: f1 f1 f1 00 00 00 00 00 00 00 00 00 00 00 f2 00
 ffff88018c43e880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88018c43e900: 00 f1 f1 f1 f1 04 f2 f2 f2 f2 f2 f2 f2 00 00 00
                                                    ^
 ffff88018c43e980: f2 f2 f2 f2 f2 f8 f2 f2 f2 00 00 00 00 00 00 00
 ffff88018c43ea00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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