linux-kernel - Re: [syzbot] [exfat?] [ocfs2?] kernel BUG in link_path

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Message-ID: <693176d2.a70a0220.d98e3.01ce.GAE@google.com>
Date: Thu, 04 Dec 2025 03:56:02 -0800
From: syzbot <syzbot+d222f4b7129379c3d5bc@...kaller.appspotmail.com>
To: brauner@...nel.org, jack@...e.cz, jlbec@...lplan.org, 
	joseph.qi@...ux.alibaba.com, linkinjeon@...nel.org, 
	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org, mark@...heh.com, 
	mjguzik@...il.com, ocfs2-devel@...ts.linux.dev, sj1557.seo@...sung.com, 
	syzkaller-bugs@...glegroups.com, viro@...iv.linux.org.uk
Subject: Re: [syzbot] [exfat?] [ocfs2?] kernel BUG in link_path_walk

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
kernel BUG in link_path_walk

VFS_BUG_ON_INODE(d_can_lookup(_dentry) && !S_ISDIR(_dentry->d_inode->i_mode)) encountered for inode ffff888074eca4f8
fs ocfs2 mode 100000 opflags 0x2 flags 0x20 state 0x0 count 2
------------[ cut here ]------------
kernel BUG at fs/namei.c:2542!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 1 UID: 0 PID: 7668 Comm: syz.0.211 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:link_path_walk+0x1d7f/0x1d90 fs/namei.c:2542
Code: e8 a6 16 ea fe 90 0f 0b e8 de 8c 83 ff 41 89 ef e9 d2 fc ff ff e8 d1 8c 83 ff 4c 89 ff 48 c7 c6 40 d6 79 8b e8 82 16 ea fe 90 <0f> 0b 66 66 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90
RSP: 0018:ffffc9000c5a78a0 EFLAGS: 00010282
RAX: 00000000000000b2 RBX: ffffc9000c5a7c20 RCX: 68650f632580b300
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffff888011640020 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff1bbae20 R12: 0000000000008000
R13: ffffc9000c5a7c28 R14: ffff888074f0a0b8 R15: ffff888074eca4f8
FS:  00007f56a8b4f6c0(0000) GS:ffff888125f3a000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f56a73fdf98 CR3: 00000000742f6000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 path_openat+0x2b3/0x3dd0 fs/namei.c:4799
 do_filp_open+0x1fa/0x410 fs/namei.c:4830
 do_sys_openat2+0x121/0x200 fs/open.c:1430
 do_sys_open fs/open.c:1436 [inline]
 __do_sys_open fs/open.c:1444 [inline]
 __se_sys_open fs/open.c:1440 [inline]
 __x64_sys_open+0x11e/0x150 fs/open.c:1440
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f56a7d8f749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f56a8b4f038 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007f56a7fe5fa0 RCX: 00007f56a7d8f749
RDX: 0000000000000000 RSI: 0000000000145142 RDI: 0000200000000240
RBP: 00007f56a7e13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f56a7fe6038 R14: 00007f56a7fe5fa0 R15: 00007ffd61dc1878
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:link_path_walk+0x1d7f/0x1d90 fs/namei.c:2542
Code: e8 a6 16 ea fe 90 0f 0b e8 de 8c 83 ff 41 89 ef e9 d2 fc ff ff e8 d1 8c 83 ff 4c 89 ff 48 c7 c6 40 d6 79 8b e8 82 16 ea fe 90 <0f> 0b 66 66 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90
RSP: 0018:ffffc9000c5a78a0 EFLAGS: 00010282
RAX: 00000000000000b2 RBX: ffffc9000c5a7c20 RCX: 68650f632580b300
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffff888011640020 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff1bbae20 R12: 0000000000008000
R13: ffffc9000c5a7c28 R14: ffff888074f0a0b8 R15: ffff888074eca4f8
FS:  00007f56a8b4f6c0(0000) GS:ffff888125f3a000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f56a73fdf98 CR3: 00000000742f6000 CR4: 00000000003526f0


Tested on:

commit:         bc04acf4 Add linux-next specific files for 20251204
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=107bd01a580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=a94030c847137a18
dashboard link: https://syzkaller.appspot.com/bug?extid=d222f4b7129379c3d5bc
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=1377401a580000