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BUG: KASAN: out-of-bounds in update_stack_state+0x5db/0x690 arch/x86/kernel/unwind_frame.c:266
Read of size 8 at addr ffff8801c725f440 by task syz-executor2/17778

CPU: 0 PID: 17778 Comm: syz-executor2 Not tainted 4.19.0-rc6+ #262
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1c4/0x2b4 lib/dump_stack.c:113
 print_address_description.cold.8+0x9/0x1ff mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report.cold.9+0x242/0x309 mm/kasan/report.c:412
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
 update_stack_state+0x5db/0x690 arch/x86/kernel/unwind_frame.c:266
 unwind_next_frame.part.7+0x1ae/0x9e0 arch/x86/kernel/unwind_frame.c:329
 unwind_next_frame+0x3e/0x50 arch/x86/kernel/unwind_frame.c:287
 __save_stack_trace+0x7d/0xf0 arch/x86/kernel/stacktrace.c:44
 save_stack_trace_tsk+0x9c/0xd0 arch/x86/kernel/stacktrace.c:76
 proc_pid_stack+0x217/0x3b0 fs/proc/base.c:424
 proc_single_show+0x101/0x190 fs/proc/base.c:723
 seq_read+0x4af/0x1150 fs/seq_file.c:229
 do_loop_readv_writev fs/read_write.c:700 [inline]
 do_iter_read+0x4a3/0x650 fs/read_write.c:924
 vfs_readv+0x175/0x1c0 fs/read_write.c:986
 do_preadv+0x1cc/0x280 fs/read_write.c:1070
 __do_sys_preadv fs/read_write.c:1120 [inline]
 __se_sys_preadv fs/read_write.c:1115 [inline]
 __x64_sys_preadv+0x9a/0xf0 fs/read_write.c:1115
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457579
Code: 1d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 eb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f71ed954c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000127
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000457579
RDX: 10000000000000fd RSI: 0000000020000480 RDI: 0000000000000006
RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f71ed9556d4
R13: 00000000004c309c R14: 00000000004d4a40 R15: 00000000ffffffff

The buggy address belongs to the page:
page:ffffea00071c97c0 count:0 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0x2fffc0000000000()
raw: 02fffc0000000000 0000000000000000 ffffffff071c0101 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801c725f300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8801c725f380: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8801c725f400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
                                              ^
 ffff8801c725f480: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8801c725f500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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