[syzbot] [bcachefs?] general protection fault in __d_lookup

[syzbot <syzbot+c97005be42b5040dfb21@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    69b8923f5003 Merge tag 'for-linus-6.14-ofs4' of git://git...
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16c2dddf980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=57ab43c279fa614d
dashboard link: https://syzkaller.appspot.com/bug?extid=c97005be42b5040dfb21
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15bf4518580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/ea84ac864e92/disk-69b8923f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/6a465997b4e0/vmlinux-69b8923f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d72b67b2bd15/bzImage-69b8923f.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/dc476a9a4569/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c97005be42b5040dfb21@syzkaller.appspotmail.com

Oops: general protection fault, probably for non-canonical address 0xfbd5a5d5a0000003: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: maybe wild-memory-access in range [0xdead4ead00000018-0xdead4ead0000001f]
CPU: 0 UID: 0 PID: 5866 Comm: udevd Not tainted 6.13.0-syzkaller-09793-g69b8923f5003 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
RIP: 0010:__d_lookup+0x20f/0x7b0 fs/dcache.c:2352
Code: 89 44 24 48 49 8d 45 04 48 89 44 24 20 49 8d 45 08 48 89 44 24 50 4c 89 7c 24 30 48 89 2c 24 48 83 c5 18 48 89 e8 48 c1 e8 03 <0f> b6 04 18 84 c0 0f 85 37 03 00 00 8b 6d 00 89 ef 44 89 f6 e8 d8
RSP: 0018:ffffc9000406f870 EFLAGS: 00010a06
RAX: 1bd5a9d5a0000003 RBX: dffffc0000000000 RCX: ffff8880319d0000
RDX: 0000000000000000 RSI: 00000000426c562e RDI: 000000009a43dfa0
RBP: dead4ead00000018 R08: ffffffff823bcc58 R09: 1ffff920000826c5
R10: dffffc0000000000 R11: fffff520000826c6 R12: ffffffff823bca94
R13: ffffc9000406fab0 R14: 00000000426c562e R15: ffff888011b42eb0
FS:  00007f8465f7dc80(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005590437eb9a8 CR3: 0000000032560000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 lookup_fast+0x79/0x590 fs/namei.c:1751
 walk_component+0x57/0x410 fs/namei.c:2110
 lookup_last fs/namei.c:2612 [inline]
 path_lookupat+0x16f/0x450 fs/namei.c:2636
 filename_lookup+0x2a3/0x670 fs/namei.c:2665
 vfs_statx+0x103/0x490 fs/stat.c:344
 vfs_fstatat+0xe5/0x130 fs/stat.c:366
 __do_sys_newfstatat fs/stat.c:530 [inline]
 __se_sys_newfstatat fs/stat.c:524 [inline]
 __x64_sys_newfstatat+0x11d/0x1a0 fs/stat.c:524
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8465b165f4
Code: 64 c7 00 09 00 00 00 83 c8 ff c3 48 89 f2 b9 00 01 00 00 48 89 fe bf 9c ff ff ff e9 00 00 00 00 41 89 ca b8 06 01 00 00 0f 05 <45> 31 c0 3d 00 f0 ff ff 76 10 48 8b 15 03 a8 0d 00 f7 d8 41 83 c8
RSP: 002b:00007ffd3486bbe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000106
RAX: ffffffffffffffda RBX: 00005590437a4e50 RCX: 00007f8465b165f4
RDX: 00007ffd3486bbf8 RSI: 00007ffd3486c088 RDI: 00000000ffffff9c
RBP: 00007ffd3486bc88 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd3486c088
R13: 00007ffd3486bbf8 R14: 0000559043794910 R15: 000055903b3dda04
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__d_lookup+0x20f/0x7b0 fs/dcache.c:2352
Code: 89 44 24 48 49 8d 45 04 48 89 44 24 20 49 8d 45 08 48 89 44 24 50 4c 89 7c 24 30 48 89 2c 24 48 83 c5 18 48 89 e8 48 c1 e8 03 <0f> b6 04 18 84 c0 0f 85 37 03 00 00 8b 6d 00 89 ef 44 89 f6 e8 d8
----------------
Code disassembly (best guess):
   0:	89 44 24 48          	mov    %eax,0x48(%rsp)
   4:	49 8d 45 04          	lea    0x4(%r13),%rax
   8:	48 89 44 24 20       	mov    %rax,0x20(%rsp)
   d:	49 8d 45 08          	lea    0x8(%r13),%rax
  11:	48 89 44 24 50       	mov    %rax,0x50(%rsp)
  16:	4c 89 7c 24 30       	mov    %r15,0x30(%rsp)
  1b:	48 89 2c 24          	mov    %rbp,(%rsp)
  1f:	48 83 c5 18          	add    $0x18,%rbp
  23:	48 89 e8             	mov    %rbp,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	0f b6 04 18          	movzbl (%rax,%rbx,1),%eax <-- trapping instruction
  2e:	84 c0                	test   %al,%al
  30:	0f 85 37 03 00 00    	jne    0x36d
  36:	8b 6d 00             	mov    0x0(%rbp),%ebp
  39:	89 ef                	mov    %ebp,%edi
  3b:	44 89 f6             	mov    %r14d,%esi
  3e:	e8                   	.byte 0xe8
  3f:	d8                   	.byte 0xd8


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