[Android 5.10] general protection fault in ovl_lookup_single

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 58c592510fcd Merge 5.10.248 into android13-5.10-lts
git tree: android13-5.10-lts
console output: https://syzkaller.appspot.com/x/log.txt?x=1162e7fa580000
kernel config: https://syzkaller.appspot.com/x/.config?x=ef167f989dba92e
dashboard link: https://syzkaller.appspot.com/bug?extid=26466157cdbd1e8c264b
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1587f8aa580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17096b22580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/5f658524a370/disk-58c59251.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ef9f5387b57b/vmlinux-58c59251.xz
kernel image: https://storage.googleapis.com/syzbot-assets/1e1f18f7534a/bzImage-58c59251.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+264661...@syzkaller.appspotmail.com

general protection fault, probably for non-canonical address 0xdffffc0000000002: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017]
CPU: 0 PID: 357 Comm: syz.2.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:ovl_lookup_positive_unlocked fs/overlayfs/namei.c:203 [inline]
RIP: 0010:ovl_lookup_single+0x89/0x870 fs/overlayfs/namei.c:226
Code: 4d cf b3 ff 48 89 c3 48 3d 01 f0 ff ff 72 0a e8 ad cc 6e ff e9 de 03 00 00 49 89 dd 49 c1 ed 03 48 b8 00 00 00 00 00 fc ff df <41> 0f b6 44 05 00 84 c0 0f 85 ce 05 00 00 44 8b 23 44 89 e6 81 e6
RSP: 0018:ffffc90002d77a78 EFLAGS: 00010203
RAX: dffffc0000000000 RBX: 0000000000000016 RCX: 32250c0bc0ebb700
RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffff8881215c12a0
RBP: ffffc90002d77ab0 R08: ffff8881215c12a7 R09: 1ffff110242b8254
R10: dffffc0000000000 R11: ffffed10242b8255 R12: ffff88810d335000
R13: 0000000000000002 R14: 0000000000000000 R15: ffffffff853ba5a0
FS: 00007f868afb66c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f868af73ff8 CR3: 000000010f03a000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
ovl_lookup_layer+0x355/0x420 fs/overlayfs/namei.c:310
ovl_lookup+0x68d/0x1750 fs/overlayfs/namei.c:909
__lookup_hash+0x114/0x250 fs/namei.c:1549
filename_create+0x1d5/0x680 fs/namei.c:3616
user_path_create fs/namei.c:3673 [inline]
do_mkdirat+0x5e/0x340 fs/namei.c:3813
__do_sys_mkdirat fs/namei.c:3831 [inline]
__se_sys_mkdirat fs/namei.c:3829 [inline]
__x64_sys_mkdirat+0x7b/0x90 fs/namei.c:3829
do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f868b151eb9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f868afb6028 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007f868b3ccfa0 RCX: 00007f868b151eb9
RDX: 0000000000000000 RSI: 0000200000002000 RDI: ffffffffffffff9c
RBP: 00007f868b1bfc1f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f868b3cd038 R14: 00007f868b3ccfa0 R15: 00007ffebc42b4f8
Modules linked in:
---[ end trace 45e50b3c85edc398 ]---
RIP: 0010:ovl_lookup_positive_unlocked fs/overlayfs/namei.c:203 [inline]
RIP: 0010:ovl_lookup_single+0x89/0x870 fs/overlayfs/namei.c:226
Code: 4d cf b3 ff 48 89 c3 48 3d 01 f0 ff ff 72 0a e8 ad cc 6e ff e9 de 03 00 00 49 89 dd 49 c1 ed 03 48 b8 00 00 00 00 00 fc ff df <41> 0f b6 44 05 00 84 c0 0f 85 ce 05 00 00 44 8b 23 44 89 e6 81 e6
RSP: 0018:ffffc90002d77a78 EFLAGS: 00010203
RAX: dffffc0000000000 RBX: 0000000000000016 RCX: 32250c0bc0ebb700
RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffff8881215c12a0
RBP: ffffc90002d77ab0 R08: ffff8881215c12a7 R09: 1ffff110242b8254
R10: dffffc0000000000 R11: ffffed10242b8255 R12: ffff88810d335000
R13: 0000000000000002 R14: 0000000000000000 R15: ffffffff853ba5a0
FS: 00007f868afb66c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f868af73ff8 CR3: 000000010f03a000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 4d cf rex.WRB iretq
2: b3 ff mov $0xff,%bl
4: 48 89 c3 mov %rax,%rbx
7: 48 3d 01 f0 ff ff cmp $0xfffffffffffff001,%rax
d: 72 0a jb 0x19
f: e8 ad cc 6e ff call 0xff6eccc1
14: e9 de 03 00 00 jmp 0x3f7
19: 49 89 dd mov %rbx,%r13
1c: 49 c1 ed 03 shr $0x3,%r13
20: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
27: fc ff df
* 2a: 41 0f b6 44 05 00 movzbl 0x0(%r13,%rax,1),%eax <-- trapping instruction
30: 84 c0 test %al,%al
32: 0f 85 ce 05 00 00 jne 0x606
38: 44 8b 23 mov (%rbx),%r12d
3b: 44 89 e6 mov %r12d,%esi
3e: 81 .byte 0x81
3f: e6 .byte 0xe6


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