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BUG: KASAN: stack-out-of-bounds in unwind_get_return_address+0x92/0xa0 arch/x86/kernel/unwind_frame.c:17
Read of size 8 at addr ffff8801cd63fdf8 by task syz-executor0/906

CPU: 0 PID: 906 Comm: syz-executor0 Not tainted 4.9.88-g71df7bb #60
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801cba0f7d0 ffffffff81d95f19 ffffea0007358fc0 ffff8801cd63fdf8
 0000000000000000 ffff8801cd63fdf8 0000000000000000 ffff8801cba0f808
 ffffffff8153e793 ffff8801cd63fdf8 0000000000000008 0000000000000000
Call Trace:
 [<ffffffff81d95f19>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81d95f19>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff8153e793>] print_address_description+0x73/0x280 mm/kasan/report.c:256
 [<ffffffff8153ec95>] kasan_report_error mm/kasan/report.c:355 [inline]
 [<ffffffff8153ec95>] kasan_report+0x255/0x380 mm/kasan/report.c:412
 [<ffffffff8153ee34>] __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
 [<ffffffff810d4e52>] unwind_get_return_address+0x92/0xa0 arch/x86/kernel/unwind_frame.c:17
 [<ffffffff8107c66d>] __save_stack_trace+0x8d/0xf0 arch/x86/kernel/stacktrace.c:43
 [<ffffffff8107c738>] save_stack_trace_tsk+0x48/0x70 arch/x86/kernel/stacktrace.c:71
 [<ffffffff816c6266>] proc_pid_stack+0x146/0x230 fs/proc/base.c:466
 [<ffffffff816c7a38>] proc_single_show+0xf8/0x170 fs/proc/base.c:768
 [<ffffffff815e9a5f>] seq_read+0x32f/0x1290 fs/seq_file.c:240
 [<ffffffff8156d338>] do_loop_readv_writev.part.17+0xc8/0x2b0 fs/read_write.c:715
 [<ffffffff8157147d>] do_loop_readv_writev fs/read_write.c:879 [inline]
 [<ffffffff8157147d>] do_readv_writev+0x5fd/0x740 fs/read_write.c:873
 [<ffffffff81571644>] vfs_readv+0x84/0xc0 fs/read_write.c:897
 [<ffffffff81571766>] do_readv+0xe6/0x250 fs/read_write.c:923
 [<ffffffff81574c37>] SYSC_readv fs/read_write.c:1010 [inline]
 [<ffffffff81574c37>] SyS_readv+0x27/0x30 fs/read_write.c:1007
 [<ffffffff81006504>] do_syscall_64+0x1a4/0x490 arch/x86/entry/common.c:282
 [<ffffffff838b7a53>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb

The buggy address belongs to the page:
page:ffffea0007358fc0 count:0 mapcount:0 mapping:          (null) index:0x0
flags: 0x8000000000000000()
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801cd63fc80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8801cd63fd00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8801cd63fd80: 00 00 f1 f1 f1 f1 00 f2 f2 f2 f2 f2 f2 f2 00 f2
                                                                ^
 ffff8801cd63fe00: f2 f2 f2 f2 f2 f2 00 00 f2 f2 00 00 00 00 00 00
 ffff8801cd63fe80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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