[syzbot] [erofs?] WARNING in erofs_iget (2)

[syzbot <syzbot+c2dd47dc153320cc4692@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    33a647c659ff Add linux-next specific files for 20260129
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=1404f93a580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=1b94612779ae7173
dashboard link: https://syzkaller.appspot.com/bug?extid=c2dd47dc153320cc4692
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=17f2a45a580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=17e5db2a580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/9d0ce0a8fecd/disk-33a647c6.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/4369620c4390/vmlinux-33a647c6.xz
kernel image: https://storage.googleapis.com/syzbot-assets/18ae695e8dfc/bzImage-33a647c6.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/d92cbdf601af/mount_0.gz
  fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=1102045a580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c2dd47dc153320cc4692@syzkaller.appspotmail.com

VFS_WARN_ON_INODE(strlen(link) != linklen): inode:ffff8880591b5fc8 fs:erofs mode:120777 opflags:0x8 flags:0x0 state:0x1 count:1
------------[ cut here ]------------
1
WARNING: ./include/linux/fs.h:953 at inode_set_cached_link include/linux/fs.h:953 [inline], CPU#1: syz-executor/5938
WARNING: ./include/linux/fs.h:953 at erofs_fill_symlink fs/erofs/inode.c:25 [inline], CPU#1: syz-executor/5938
WARNING: ./include/linux/fs.h:953 at erofs_read_inode fs/erofs/inode.c:160 [inline], CPU#1: syz-executor/5938
WARNING: ./include/linux/fs.h:953 at erofs_fill_inode fs/erofs/inode.c:216 [inline], CPU#1: syz-executor/5938
WARNING: ./include/linux/fs.h:953 at erofs_iget+0x1f4d/0x2b10 fs/erofs/inode.c:285, CPU#1: syz-executor/5938
Modules linked in:
CPU: 1 UID: 0 PID: 5938 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
RIP: 0010:inode_set_cached_link include/linux/fs.h:953 [inline]
RIP: 0010:erofs_fill_symlink fs/erofs/inode.c:25 [inline]
RIP: 0010:erofs_read_inode fs/erofs/inode.c:160 [inline]
RIP: 0010:erofs_fill_inode fs/erofs/inode.c:216 [inline]
RIP: 0010:erofs_iget+0x1f4d/0x2b10 fs/erofs/inode.c:285
Code: 0f 8c 65 e2 ff ff 48 89 df e8 ff 10 e3 fd e9 58 e2 ff ff e8 d5 af 79 fd 48 8b 7c 24 10 48 c7 c6 e0 7f 1e 8c e8 c4 a7 fd fd 90 <0f> 0b 90 e9 3c fe ff ff e8 b6 af 79 fd 48 8b 7c 24 10 48 c7 c6 60
RSP: 0018:ffffc900043bf780 EFLAGS: 00010246
RAX: 8b808a9eaf282f00 RBX: 0000000000000017 RCX: 8b808a9eaf282f00
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: ffffc900043bf9a0 R08: ffffc900043bf367 R09: 1ffff92000877e6c
R10: dffffc0000000000 R11: fffff52000877e6d R12: 0000000000000027
R13: 1ffff1100b236c03 R14: 0000000000000027 R15: ffff888027ca6d80
FS:  0000555581765500(0000) GS:ffff8881253a4000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555581790aa8 CR3: 000000007f6b8000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 erofs_lookup+0x186/0x320 fs/erofs/namei.c:214
 __lookup_slow+0x2b7/0x410 fs/namei.c:1916
 lookup_slow+0x53/0x70 fs/namei.c:1933
 walk_component fs/namei.c:2279 [inline]
 lookup_last fs/namei.c:2780 [inline]
 path_lookupat+0x3f5/0x8c0 fs/namei.c:2804
 filename_lookup+0x256/0x5d0 fs/namei.c:2833
 user_path_at+0x40/0x160 fs/namei.c:3612
 ksys_umount fs/namespace.c:2052 [inline]
 __do_sys_umount fs/namespace.c:2060 [inline]
 __se_sys_umount fs/namespace.c:2058 [inline]
 __x64_sys_umount+0xf6/0x170 fs/namespace.c:2058
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f995879c117
Code: a2 c7 05 7c 94 24 00 00 00 00 00 eb 96 e8 e1 12 00 00 90 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffcc0f75bd8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f995879c117
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffcc0f75c90
RBP: 00007ffcc0f75c90 R08: 00007ffcc0f76c90 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffcc0f76d80
R13: 00007f995880471f R14: 00005555817654e8 R15: 00007ffcc0f78f40
 </TASK>


---
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