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BUG: KASAN: stack-out-of-bounds in unwind_get_return_address+0x8f/0xa0 arch/x86/kernel/unwind_frame.c:17
Read of size 8 at addr ffff8801aa10fde8 by task syz-executor2/4500

CPU: 1 PID: 4500 Comm: syz-executor2 Not tainted 4.9.125+ #41
 ffff8801c52b77c8 ffffffff81af0ae9 ffffea0006a843c0 ffff8801aa10fde8
 0000000000000000 ffff8801aa10fde8 ffff8801c51188c0 ffff8801c52b7800
 ffffffff814e0e1d ffff8801aa10fde8 0000000000000008 0000000000000000
Call Trace:
 [<ffffffff81af0ae9>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81af0ae9>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff814e0e1d>] print_address_description+0x6c/0x234 mm/kasan/report.c:256
 [<ffffffff814e1227>] kasan_report_error mm/kasan/report.c:355 [inline]
 [<ffffffff814e1227>] kasan_report.cold.6+0x242/0x2fe mm/kasan/report.c:412
 [<ffffffff814d3664>] __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
 [<ffffffff810aa8df>] unwind_get_return_address+0x8f/0xa0 arch/x86/kernel/unwind_frame.c:17
 [<ffffffff81075fbd>] __save_stack_trace+0x8d/0xf0 arch/x86/kernel/stacktrace.c:43
 [<ffffffff81076088>] save_stack_trace_tsk+0x48/0x70 arch/x86/kernel/stacktrace.c:71
 [<ffffffff8163dcc8>] proc_pid_stack+0x148/0x220 fs/proc/base.c:469
 [<ffffffff8163624d>] proc_single_show+0xfd/0x170 fs/proc/base.c:771
 [<ffffffff8155e8f6>] seq_read+0x4b6/0x12d0 fs/seq_file.c:240
 [<ffffffff814ea255>] do_loop_readv_writev.part.1+0xd5/0x280 fs/read_write.c:718
 [<ffffffff814ecb70>] do_loop_readv_writev fs/read_write.c:707 [inline]
 [<ffffffff814ecb70>] compat_do_readv_writev+0x570/0x7b0 fs/read_write.c:1091
 [<ffffffff814ece92>] compat_readv+0xe2/0x150 fs/read_write.c:1120
 [<ffffffff814ed222>] do_compat_preadv64+0x152/0x180 fs/read_write.c:1169
 [<ffffffff814ef7ab>] C_SYSC_preadv fs/read_write.c:1189 [inline]
 [<ffffffff814ef7ab>] compat_SyS_preadv+0x3b/0x50 fs/read_write.c:1183
 [<ffffffff81005fd1>] do_syscall_32_irqs_on arch/x86/entry/common.c:325 [inline]
 [<ffffffff81005fd1>] do_fast_syscall_32+0x2f1/0x860 arch/x86/entry/common.c:387
 [<ffffffff8278d6e0>] entry_SYSENTER_compat+0x90/0xa2 arch/x86/entry/entry_64_compat.S:137

The buggy address belongs to the page:
page:ffffea0006a843c0 count:0 mapcount:0 mapping:          (null) index:0x0
flags: 0x4000000000000000()
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801aa10fc80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8801aa10fd00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8801aa10fd80: f1 f1 f1 f1 00 f2 f2 f2 f2 f2 f2 f2 00 f2 f2 f2
                                                          ^
 ffff8801aa10fe00: f2 f2 f2 f2 00 00 f2 f2 00 00 00 00 00 00 00 00
 ffff8801aa10fe80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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