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BUG: KASAN: out-of-bounds in unwind_next_frame+0x1571/0x17a0 arch/x86/kernel/unwind_orc.c:470
Read of size 8 at addr ffff88815daff978 by task syz-executor.5/14966

CPU: 0 PID: 14966 Comm: syz-executor.5 Not tainted 4.14.179-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x13e/0x194 lib/dump_stack.c:58
 print_address_description.cold+0x7c/0x1e2 mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report mm/kasan/report.c:409 [inline]
 kasan_report.cold+0xa9/0x2ae mm/kasan/report.c:393
 unwind_next_frame+0x1571/0x17a0 arch/x86/kernel/unwind_orc.c:470
 __save_stack_trace+0x6b/0xd0 arch/x86/kernel/stacktrace.c:44
 save_stack_trace_tsk arch/x86/kernel/stacktrace.c:73 [inline]
 save_stack_trace_tsk+0x34/0x40 arch/x86/kernel/stacktrace.c:68
 proc_pid_stack+0x164/0x240 fs/proc/base.c:459
 proc_single_show+0xe7/0x150 fs/proc/base.c:761
 seq_read+0x4d2/0x1160 fs/seq_file.c:237
 do_loop_readv_writev fs/read_write.c:695 [inline]
 do_loop_readv_writev fs/read_write.c:682 [inline]
 do_iter_read+0x3e3/0x5a0 fs/read_write.c:919
 vfs_readv+0xd3/0x130 fs/read_write.c:981
 do_preadv+0x161/0x200 fs/read_write.c:1065
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45c829
RSP: 002b:00007f1351ea4c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000127
RAX: ffffffffffffffda RBX: 00000000004fa460 RCX: 000000000045c829
RDX: 000000000000037d RSI: 0000000020000500 RDI: 0000000000000006
RBP: 000000000078bfa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000862 R14: 00000000004cb23c R15: 00007f1351ea56d4

The buggy address belongs to the page:
page:ffffea000576bfc0 count:0 mapcount:0 mapping:          (null) index:0x0
flags: 0x57ffe0000000000()
raw: 057ffe0000000000 0000000000000000 0000000000000000 00000000ffffffff
raw: 0000000000000000 0000000100000001 0000000000000000 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88815daff880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88815daff900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88815daff980: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
                   ^
 ffff88815daffa00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88815daffa80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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