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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+0x194/0x2330 arch/x86/kernel/unwind_orc.c:428
Read of size 8 at addr ffff88802d9af070 by task syz-executor.3/28681

CPU: 1 PID: 28681 Comm: syz-executor.3 Not tainted 5.4.56-syzkaller-00005-g8555f0d9d303 #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+0x14a/0x1ce lib/dump_stack.c:118
 print_address_description+0x93/0x620 mm/kasan/report.c:374
 __kasan_report+0x16d/0x1e0 mm/kasan/report.c:506
 kasan_report+0x36/0x60 mm/kasan/common.c:634
 user_mode arch/x86/include/asm/ptrace.h:131 [inline]
 unwind_next_frame+0x194/0x2330 arch/x86/kernel/unwind_orc.c:428
 arch_stack_walk+0xf4/0x120 arch/x86/kernel/stacktrace.c:25
 stack_trace_save_tsk+0x2e7/0x490 kernel/stacktrace.c:151
 proc_pid_stack+0x12f/0x1f0 fs/proc/base.c:455
 proc_single_show+0xd3/0x130 fs/proc/base.c:757
 seq_read+0x4aa/0xd30 fs/seq_file.c:229
 do_loop_readv_writev fs/read_write.c:717 [inline]
 do_iter_read+0x43b/0x550 fs/read_write.c:938
 vfs_readv fs/read_write.c:1000 [inline]
 do_preadv+0x213/0x350 fs/read_write.c:1092
 do_syscall_64+0xcb/0x150 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45ccd9
Code: 2d b6 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 fb b5 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fbf5a9f1c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000127
RAX: ffffffffffffffda RBX: 0000000000024a80 RCX: 000000000045ccd9
RDX: 0000000000000375 RSI: 00000000200017c0 RDI: 0000000000000006
RBP: 000000000078c090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078c04c
R13: 00007ffd7c7965df R14: 00007fbf5a9f29c0 R15: 000000000078c04c

The buggy address belongs to the page:
page:ffffea0000b66bc0 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1
flags: 0x4000000000000000()
raw: 4000000000000000 dead000000000100 dead000000000122 0000000000000000
raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88802d9aef00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88802d9aef80: 00 00 00 00 f1 f1 f1 f1 00 00 f3 f3 00 00 00 00
>ffff88802d9af000: 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00 f3 f3 f3
                                                             ^
 ffff88802d9af080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88802d9af100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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