BUG: KASAN: stack-out-of-bounds in user_mode arch/x86/include/asm/ptrace.h:131 [inline]
BUG: KASAN: stack-out-of-bounds in unwind_next_frame+0x1be/0x27b0 arch/x86/kernel/unwind_orc.c:421
Read of size 8 at addr ffff8881e9077c80 by task syz-executor.0/639

CPU: 1 PID: 639 Comm: syz-executor.0 Not tainted 5.4.116-syzkaller-00428-g546a6e8726bc #0
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+0x1d8/0x24e lib/dump_stack.c:118
 print_address_description+0x9b/0x650 mm/kasan/report.c:384
 __kasan_report+0x182/0x260 mm/kasan/report.c:516
 kasan_report+0x30/0x60 mm/kasan/common.c:641
 user_mode arch/x86/include/asm/ptrace.h:131 [inline]
 unwind_next_frame+0x1be/0x27b0 arch/x86/kernel/unwind_orc.c:421
 arch_stack_walk+0x114/0x140 arch/x86/kernel/stacktrace.c:25
 stack_trace_save_tsk+0x17c/0x270 kernel/stacktrace.c:151
 proc_pid_stack+0x126/0x1f0 fs/proc/base.c:455
 proc_single_show+0xd3/0x120 fs/proc/base.c:757
 seq_read+0x4aa/0xd10 fs/seq_file.c:229
 do_loop_readv_writev fs/read_write.c:714 [inline]
 do_iter_read+0x41b/0x5c0 fs/read_write.c:935
 vfs_readv fs/read_write.c:997 [inline]
 do_preadv+0x20d/0x350 fs/read_write.c:1089
 do_syscall_64+0xcb/0x1e0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x4665f9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f9dde4cc188 EFLAGS: 00000246 ORIG_RAX: 0000000000000127
RAX: ffffffffffffffda RBX: 000000000056bf60 RCX: 00000000004665f9
RDX: 0000000000000375 RSI: 00000000200017c0 RDI: 0000000000000005
RBP: 00000000004bfce1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf60
R13: 00007ffe55fd42cf R14: 00007f9dde4cc300 R15: 0000000000022000

The buggy address belongs to the page:
page:ffffea0007a41dc0 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0x8000000000000000()
raw: 8000000000000000 0000000000000000 ffffea0007a41dc8 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8881e9077b80: 00 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8881e9077c00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8881e9077c80: f1 f1 f1 f1 00 f2 f2 f2 00 00 f3 f3 00 00 00 00
                   ^
 ffff8881e9077d00: 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1
 ffff8881e9077d80: 00 00 00 00 00 00 00 00 00 00 f3 f3 f3 f3 f3 f3
==================================================================