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BUG: KASAN: out-of-bounds in unwind_next_frame+0xd7/0xe0 arch/x86/kernel/unwind_frame.c:51
Read of size 8 at addr ffff8801d70678e0 by task syz-executor0/3948

CPU: 0 PID: 3948 Comm: syz-executor0 Not tainted 4.9.91-gcc88c05 #9
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d70c7810 ffffffff81d95109 ffffea00075c19c0 ffff8801d70678e0
 0000000000000000 ffff8801d70678e8 0000000000000000 ffff8801d70c7848
 ffffffff8153d5d3 ffff8801d70678e0 0000000000000008 0000000000000000
Call Trace:
 [<ffffffff81d95109>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81d95109>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff8153d5d3>] print_address_description+0x73/0x280 mm/kasan/report.c:256
 [<ffffffff8153dad5>] kasan_report_error mm/kasan/report.c:355 [inline]
 [<ffffffff8153dad5>] kasan_report+0x255/0x380 mm/kasan/report.c:412
 [<ffffffff8153dc74>] __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
 [<ffffffff810d6147>] unwind_next_frame+0xd7/0xe0 arch/x86/kernel/unwind_frame.c:51
 [<ffffffff8107c7fd>] __save_stack_trace+0x7d/0xf0 arch/x86/kernel/stacktrace.c:42
 [<ffffffff8107c8d8>] save_stack_trace_tsk+0x48/0x70 arch/x86/kernel/stacktrace.c:71
 [<ffffffff816c5006>] proc_pid_stack+0x146/0x230 fs/proc/base.c:466
 [<ffffffff816c67d8>] proc_single_show+0xf8/0x170 fs/proc/base.c:768
 [<ffffffff815e87ff>] seq_read+0x32f/0x1290 fs/seq_file.c:240
 [<ffffffff8156c168>] do_loop_readv_writev.part.17+0xc8/0x2b0 fs/read_write.c:715
 [<ffffffff8157134f>] do_loop_readv_writev fs/read_write.c:1097 [inline]
 [<ffffffff8157134f>] compat_do_readv_writev+0x5ff/0x740 fs/read_write.c:1091
 [<ffffffff81571573>] compat_readv+0xe3/0x150 fs/read_write.c:1120
 [<ffffffff81571886>] do_compat_preadv64+0xd6/0x100 fs/read_write.c:1169
 [<ffffffff81573ccb>] C_SYSC_preadv fs/read_write.c:1189 [inline]
 [<ffffffff81573ccb>] compat_SyS_preadv+0x3b/0x50 fs/read_write.c:1183
 [<ffffffff81006f95>] do_syscall_32_irqs_on arch/x86/entry/common.c:325 [inline]
 [<ffffffff81006f95>] do_fast_syscall_32+0x2f5/0x870 arch/x86/entry/common.c:387
 [<ffffffff838b9b90>] entry_SYSENTER_compat+0x90/0xa2 arch/x86/entry/entry_64_compat.S:137

The buggy address belongs to the page:
page:ffffea00075c19c0 count:0 mapcount:0 mapping:          (null) index:0x0
flags: 0x8000000000000000()
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801d7067780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8801d7067800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8801d7067880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
                                                          ^
 ffff8801d7067900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8801d7067980: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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