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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+0x368/0x3b0 arch/x86/kernel/unwind_frame.c:76
Read of size 8 at addr ffff8801a66ff810 by task syz-executor0/21321

CPU: 0 PID: 21321 Comm: syz-executor0 Not tainted 4.9.124+ #87
 ffff8801be5d7788 ffffffff81af03d9 ffffea000699bfc0 ffff8801a66ff810
 0000000000000000 ffff8801a66ff818 ffff8801a82817c0 ffff8801be5d77c0
 ffffffff814e0d7d ffff8801a66ff810 0000000000000008 0000000000000000
Call Trace:
 [<ffffffff81af03d9>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81af03d9>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff814e0d7d>] print_address_description+0x6c/0x234 mm/kasan/report.c:256
 [<ffffffff814e1187>] kasan_report_error mm/kasan/report.c:355 [inline]
 [<ffffffff814e1187>] kasan_report.cold.6+0x242/0x2fe mm/kasan/report.c:412
 [<ffffffff814d35c4>] __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
 [<ffffffff810aae08>] get_frame_pointer arch/x86/include/asm/stacktrace.h:64 [inline]
 [<ffffffff810aae08>] __unwind_start+0x368/0x3b0 arch/x86/kernel/unwind_frame.c:76
 [<ffffffff81075f39>] unwind_start arch/x86/include/asm/unwind.h:39 [inline]
 [<ffffffff81075f39>] __save_stack_trace+0x59/0xf0 arch/x86/kernel/stacktrace.c:41
 [<ffffffff81076038>] save_stack_trace_tsk+0x48/0x70 arch/x86/kernel/stacktrace.c:71
 [<ffffffff8163dc28>] proc_pid_stack+0x148/0x220 fs/proc/base.c:469
 [<ffffffff816361ad>] proc_single_show+0xfd/0x170 fs/proc/base.c:771
 [<ffffffff8155e856>] seq_read+0x4b6/0x12d0 fs/seq_file.c:240
 [<ffffffff814ea1b5>] do_loop_readv_writev.part.1+0xd5/0x280 fs/read_write.c:718
 [<ffffffff814eb85e>] do_loop_readv_writev fs/read_write.c:707 [inline]
 [<ffffffff814eb85e>] do_readv_writev+0x56e/0x7b0 fs/read_write.c:873
 [<ffffffff814ebb24>] vfs_readv+0x84/0xc0 fs/read_write.c:897
 [<ffffffff814ebf57>] do_preadv+0x197/0x240 fs/read_write.c:974
 [<ffffffff814ef510>] SYSC_preadv fs/read_write.c:1024 [inline]
 [<ffffffff814ef510>] SyS_preadv+0x30/0x40 fs/read_write.c:1019
 [<ffffffff8100554f>] do_syscall_64+0x19f/0x480 arch/x86/entry/common.c:282
 [<ffffffff8278b793>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb

The buggy address belongs to the page:
page:ffffea000699bfc0 count:0 mapcount:0 mapping:          (null) index:0x0
flags: 0x4000000000000000()
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801a66ff700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8801a66ff780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8801a66ff800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
                            ^
 ffff8801a66ff880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8801a66ff900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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