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BUG: KASAN: out-of-bounds in get_frame_pointer arch/x86/include/asm/stacktrace.h:64 [inline]
BUG: KASAN: out-of-bounds in __unwind_start+0x3a7/0x3c0 arch/x86/kernel/unwind_frame.c:76
Read of size 8 at addr ffff8801c8b87850 by task syzkaller877355/3334

CPU: 0 PID: 3334 Comm: syzkaller877355 Not tainted 4.9.77-ge12a9c4 #27
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801c807f778 ffffffff81d941c9 ffffea000722e1c0 ffff8801c8b87850
 0000000000000000 ffff8801c8b87858 ffff8801c807f8a8 ffff8801c807f7b0
 ffffffff8153db93 ffff8801c8b87850 0000000000000008 0000000000000000
Call Trace:
 [<ffffffff81d941c9>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81d941c9>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff8153db93>] print_address_description+0x73/0x280 mm/kasan/report.c:252
 [<ffffffff8153e0b5>] kasan_report_error mm/kasan/report.c:351 [inline]
 [<ffffffff8153e0b5>] kasan_report+0x275/0x360 mm/kasan/report.c:408
 [<ffffffff8153e214>] __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:429
 [<ffffffff810d5397>] get_frame_pointer arch/x86/include/asm/stacktrace.h:64 [inline]
 [<ffffffff810d5397>] __unwind_start+0x3a7/0x3c0 arch/x86/kernel/unwind_frame.c:76
 [<ffffffff8107c689>] unwind_start arch/x86/include/asm/unwind.h:39 [inline]
 [<ffffffff8107c689>] __save_stack_trace+0x59/0xf0 arch/x86/kernel/stacktrace.c:41
 [<ffffffff8107c788>] save_stack_trace_tsk+0x48/0x70 arch/x86/kernel/stacktrace.c:71
 [<ffffffff816c4f46>] proc_pid_stack+0x146/0x230 fs/proc/base.c:466
 [<ffffffff816c6718>] proc_single_show+0xf8/0x170 fs/proc/base.c:768
 [<ffffffff815e5441>] traverse+0x231/0x900 fs/seq_file.c:124
 [<ffffffff815e8d0a>] seq_read+0x7ea/0x1290 fs/seq_file.c:195
 [<ffffffff8156b9e3>] __vfs_read+0x103/0x670 fs/read_write.c:452
 [<ffffffff8156f77e>] vfs_read+0x11e/0x380 fs/read_write.c:475
 [<ffffffff8157386f>] SYSC_pread64 fs/read_write.c:629 [inline]
 [<ffffffff8157386f>] SyS_pread64+0x13f/0x170 fs/read_write.c:616
 [<ffffffff8111cee9>] sys32_pread+0x39/0x50 arch/x86/ia32/sys_ia32.c:179
 [<ffffffff81006fc7>] do_syscall_32_irqs_on arch/x86/entry/common.c:322 [inline]
 [<ffffffff81006fc7>] do_fast_syscall_32+0x2f7/0x890 arch/x86/entry/common.c:384
 [<ffffffff838b44b4>] entry_SYSENTER_compat+0x74/0x83 arch/x86/entry/entry_64_compat.S:127

The buggy address belongs to the page:
page:ffffea000722e1c0 count:0 mapcount:0 mapping:          (null) index:0x0
flags: 0x8000000000000000()
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801c8b87700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8801c8b87780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8801c8b87800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
                                                    ^
 ffff8801c8b87880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8801c8b87900: 00 00 f1 f1 f1 f1 00 f2 f2 f2 f3 f3 f3 f3 00 00
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