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BUG: KASAN: out-of-bounds in unwind_next_frame+0xcd/0xe0 arch/x86/kernel/unwind_frame.c:51
Read of size 8 at addr ffff8801a34df838 by task syz-executor5/19246

CPU: 1 PID: 19246 Comm: syz-executor5 Not tainted 4.9.118-g856452b #21
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801ca7ef7b8 ffffffff81eb4b89 ffffea00068d37c0 ffff8801a34df838
 0000000000000000 ffff8801a34df840 ffff8801bcb69280 ffff8801ca7ef7f0
 ffffffff81567f29 ffff8801a34df838 0000000000000008 0000000000000000
Call Trace:
 [<ffffffff81eb4b89>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81eb4b89>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81567f29>] print_address_description+0x6c/0x234 mm/kasan/report.c:256
 [<ffffffff81568333>] kasan_report_error mm/kasan/report.c:355 [inline]
 [<ffffffff81568333>] kasan_report.cold.6+0x242/0x2fe mm/kasan/report.c:412
 [<ffffffff8153beb4>] __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
 [<ffffffff810d2ead>] unwind_next_frame+0xcd/0xe0 arch/x86/kernel/unwind_frame.c:51
 [<ffffffff8107b9cd>] __save_stack_trace+0x7d/0xf0 arch/x86/kernel/stacktrace.c:42
 [<ffffffff8107baa8>] save_stack_trace_tsk+0x48/0x70 arch/x86/kernel/stacktrace.c:71
 [<ffffffff816d7dc8>] proc_pid_stack+0x148/0x220 fs/proc/base.c:469
 [<ffffffff816d94bd>] proc_single_show+0xfd/0x170 fs/proc/base.c:771
 [<ffffffff815ed7b6>] seq_read+0x4b6/0x12e0 fs/seq_file.c:240
 [<ffffffff8156f7b5>] do_loop_readv_writev.part.18+0xd5/0x280 fs/read_write.c:718
 [<ffffffff81573705>] do_loop_readv_writev fs/read_write.c:707 [inline]
 [<ffffffff81573705>] do_readv_writev+0x565/0x7a0 fs/read_write.c:873
 [<ffffffff815739c4>] vfs_readv+0x84/0xc0 fs/read_write.c:897
 [<ffffffff81573df7>] do_preadv+0x197/0x240 fs/read_write.c:974
 [<ffffffff815773b0>] SYSC_preadv fs/read_write.c:1024 [inline]
 [<ffffffff815773b0>] SyS_preadv+0x30/0x40 fs/read_write.c:1019
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839fca93>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb

The buggy address belongs to the page:
page:ffffea00068d37c0 count:0 mapcount:0 mapping:          (null) index:0x0
flags: 0x8000000000000000()
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801a34df700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8801a34df780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8801a34df800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
                                           ^
 ffff8801a34df880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8801a34df900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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