[Android 5.10] general protection fault in configfs_mkdir

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 30b93835619a Merge 3f7778b7513c ("xfrm: propagate extack t..
git tree: android13-5.10-lts
console output: https://syzkaller.appspot.com/x/log.txt?x=1141c58e580000
kernel config: https://syzkaller.appspot.com/x/.config?x=40fa24cc6888ca30
dashboard link: https://syzkaller.appspot.com/bug?extid=1837f5018c2bae505fca
compiler: Debian clang version 22.1.8 (1~deb13u4), Debian LLD 22.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15a1eb71580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1736a305580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/35789e4b521d/disk-30b93835.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f465d075e55e/vmlinux-30b93835.xz
kernel image: https://storage.googleapis.com/syzbot-assets/97bc968b009a/bzImage-30b93835.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+1837f5...@syzkaller.appspotmail.com

RBP: 00007ffd65563c90 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007f7830701fac R14: 00007f7830701fa0 R15: 00007f7830701fa0
general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 PID: 368 Comm: syz.2.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
RIP: 0010:configfs_mkdir+0x9c0/0xd90 fs/configfs/dir.c:1455
Code: 48 c1 e8 03 80 3c 10 00 74 08 48 89 df e8 f8 8d d6 ff 48 8b 13 48 8d 7a 04 48 89 f8 48 c1 e8 03 48 bb 00 00 00 00 00 fc ff df <0f> b6 04 18 84 c0 0f 85 4c 03 00 00 44 89 7a 04 48 83 c2 08 48 89
RSP: 0018:ffffc90000c27ca0 EFLAGS: 00010247
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: ffffc90000c27e18 R08: ffffc90000c27d8f R09: ffffc90000c27d40
R10: dffffc0000000000 R11: fffff52000184fb2 R12: 000000000000ee01
R13: 00000000fffffff4 R14: 1ffff92000184fa4 R15: 0000000000000000
FS: 000055557b9c4500(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b33763fff CR3: 0000000124941000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
vfs_mkdir+0x42c/0x600 fs/namei.c:3840
do_mkdirat+0x14c/0x340 fs/namei.c:3862
__do_sys_mkdirat fs/namei.c:3873 [inline]
__se_sys_mkdirat fs/namei.c:3871 [inline]
__x64_sys_mkdirat+0x7b/0x90 fs/namei.c:3871
do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f783047b559
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:00007ffd65563c28 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007f7830701fa0 RCX: 00007f783047b559
RDX: 00000000000001c0 RSI: 0000200000000440 RDI: ffffffffffffff9c
RBP: 00007ffd65563c90 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007f7830701fac R14: 00007f7830701fa0 R15: 00007f7830701fa0
Modules linked in:
---[ end trace 341ff55ad473a19d ]---
RIP: 0010:configfs_mkdir+0x9c0/0xd90 fs/configfs/dir.c:1455
Code: 48 c1 e8 03 80 3c 10 00 74 08 48 89 df e8 f8 8d d6 ff 48 8b 13 48 8d 7a 04 48 89 f8 48 c1 e8 03 48 bb 00 00 00 00 00 fc ff df <0f> b6 04 18 84 c0 0f 85 4c 03 00 00 44 89 7a 04 48 83 c2 08 48 89
RSP: 0018:ffffc90000c27ca0 EFLAGS: 00010247
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: ffffc90000c27e18 R08: ffffc90000c27d8f R09: ffffc90000c27d40
R10: dffffc0000000000 R11: fffff52000184fb2 R12: 000000000000ee01
R13: 00000000fffffff4 R14: 1ffff92000184fa4 R15: 0000000000000000
FS: 000055557b9c4500(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055691010ed00 CR3: 0000000124941000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 48 c1 e8 03 shr $0x3,%rax
4: 80 3c 10 00 cmpb $0x0,(%rax,%rdx,1)
8: 74 08 je 0x12
a: 48 89 df mov %rbx,%rdi
d: e8 f8 8d d6 ff call 0xffd68e0a
12: 48 8b 13 mov (%rbx),%rdx
15: 48 8d 7a 04 lea 0x4(%rdx),%rdi
19: 48 89 f8 mov %rdi,%rax
1c: 48 c1 e8 03 shr $0x3,%rax
20: 48 bb 00 00 00 00 00 movabs $0xdffffc0000000000,%rbx
27: fc ff df
* 2a: 0f b6 04 18 movzbl (%rax,%rbx,1),%eax <-- trapping instruction
2e: 84 c0 test %al,%al
30: 0f 85 4c 03 00 00 jne 0x382
36: 44 89 7a 04 mov %r15d,0x4(%rdx)
3a: 48 83 c2 08 add $0x8,%rdx
3e: 48 rex.W
3f: 89 .byte 0x89


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