* [PATCH] Fix a drop_nlink warning in minix_rename
@ 2025-11-02 18:25 Jori Koolstra
2025-11-03 4:42 ` kernel test robot
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Jori Koolstra @ 2025-11-02 18:25 UTC (permalink / raw)
To: Christian Brauner, Tetsuo Handa, Taotao Chen, Jeff Layton,
Jan Kara, NeilBrown
Cc: jkoolstra, linux-kernel, syzbot+a65e824272c5f741247d
Syzbot found a drop_nlink warning that is triggered by an easy to
detect nlink corruption. This patch adds sanity checks to minix_unlink
and minix_rename to prevent the warning and instead return EFSCORRUPTED
to the caller.
The changes were tested using the syzbot reproducer as well as local
testing.
Signed-off-by: Jori Koolstra <jkoolstra@xs4all.nl>
Reported-by: syzbot+a65e824272c5f741247d@syzkaller.appspotmail.com
Closes: https://syzbot.org/bug?extid=a65e824272c5f741247d
---
fs/minix/namei.c | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/fs/minix/namei.c b/fs/minix/namei.c
index a8d5a7e22b7b..4bc1d9c31284 100644
--- a/fs/minix/namei.c
+++ b/fs/minix/namei.c
@@ -145,6 +145,12 @@ static int minix_unlink(struct inode * dir, struct dentry *dentry)
struct minix_dir_entry * de;
int err;
+ if (inode->i_nlink < 1) {
+ printk(KERN_CRIT "minix-fs error: inode (ino: %ld) "
+ "has corrupted nlink", inode->i_ino);
+ return -EFSCORRUPTED;
+ }
+
de = minix_find_entry(dentry, &folio);
if (!de)
return -ENOENT;
@@ -218,6 +224,13 @@ static int minix_rename(struct mnt_idmap *idmap,
if (dir_de && !minix_empty_dir(new_inode))
goto out_dir;
+ err = -EFSCORRUPTED;
+ if (new_inode->i_nlink == 0 || (dir_de && new_inode->i_nlink != 2)) {
+ printk(KERN_CRIT "minix-fs error: inode (ino: %ld) "
+ "has corrupted nlink", new_inode->i_ino);
+ goto out_dir;
+ }
+
err = -ENOENT;
new_de = minix_find_entry(new_dentry, &new_folio);
if (!new_de)
--
2.51.1.dirty
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] Fix a drop_nlink warning in minix_rename
2025-11-02 18:25 [PATCH] Fix a drop_nlink warning in minix_rename Jori Koolstra
@ 2025-11-03 4:42 ` kernel test robot
2025-11-03 7:58 ` kernel test robot
2025-11-04 8:03 ` Jan Kara
2 siblings, 0 replies; 4+ messages in thread
From: kernel test robot @ 2025-11-03 4:42 UTC (permalink / raw)
To: Jori Koolstra, Christian Brauner, Tetsuo Handa, Taotao Chen,
Jeff Layton, Jan Kara, NeilBrown
Cc: oe-kbuild-all, jkoolstra, linux-kernel,
syzbot+a65e824272c5f741247d
Hi Jori,
kernel test robot noticed the following build errors:
[auto build test ERROR on brauner-vfs/vfs.all]
[also build test ERROR on linus/master v6.18-rc4 next-20251031]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Jori-Koolstra/Fix-a-drop_nlink-warning-in-minix_rename/20251103-022646
base: https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git vfs.all
patch link: https://lore.kernel.org/r/20251102182532.2442670-1-jkoolstra%40xs4all.nl
patch subject: [PATCH] Fix a drop_nlink warning in minix_rename
config: arc-randconfig-r073-20251103 (https://download.01.org/0day-ci/archive/20251103/202511031229.rqpKLU46-lkp@intel.com/config)
compiler: arc-linux-gcc (GCC) 8.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251103/202511031229.rqpKLU46-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202511031229.rqpKLU46-lkp@intel.com/
All errors (new ones prefixed by >>):
fs/minix/namei.c: In function 'minix_unlink':
>> fs/minix/namei.c:151:11: error: 'EFSCORRUPTED' undeclared (first use in this function); did you mean 'FS_NRSUPER'?
return -EFSCORRUPTED;
^~~~~~~~~~~~
FS_NRSUPER
fs/minix/namei.c:151:11: note: each undeclared identifier is reported only once for each function it appears in
fs/minix/namei.c: In function 'minix_rename':
fs/minix/namei.c:217:10: error: 'EFSCORRUPTED' undeclared (first use in this function); did you mean 'FS_NRSUPER'?
err = -EFSCORRUPTED;
^~~~~~~~~~~~
FS_NRSUPER
vim +151 fs/minix/namei.c
140
141 static int minix_unlink(struct inode * dir, struct dentry *dentry)
142 {
143 struct inode * inode = d_inode(dentry);
144 struct folio *folio;
145 struct minix_dir_entry * de;
146 int err;
147
148 if (inode->i_nlink < 1) {
149 printk(KERN_CRIT "minix-fs error: inode (ino: %ld) "
150 "has corrupted nlink", inode->i_ino);
> 151 return -EFSCORRUPTED;
152 }
153
154 de = minix_find_entry(dentry, &folio);
155 if (!de)
156 return -ENOENT;
157 err = minix_delete_entry(de, folio);
158 folio_release_kmap(folio, de);
159
160 if (err)
161 return err;
162 inode_set_ctime_to_ts(inode, inode_get_ctime(dir));
163 inode_dec_link_count(inode);
164 return 0;
165 }
166
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] Fix a drop_nlink warning in minix_rename
2025-11-02 18:25 [PATCH] Fix a drop_nlink warning in minix_rename Jori Koolstra
2025-11-03 4:42 ` kernel test robot
@ 2025-11-03 7:58 ` kernel test robot
2025-11-04 8:03 ` Jan Kara
2 siblings, 0 replies; 4+ messages in thread
From: kernel test robot @ 2025-11-03 7:58 UTC (permalink / raw)
To: Jori Koolstra, Christian Brauner, Tetsuo Handa, Taotao Chen,
Jeff Layton, Jan Kara, NeilBrown
Cc: llvm, oe-kbuild-all, jkoolstra, linux-kernel,
syzbot+a65e824272c5f741247d
Hi Jori,
kernel test robot noticed the following build errors:
[auto build test ERROR on brauner-vfs/vfs.all]
[also build test ERROR on linus/master v6.18-rc4 next-20251103]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Jori-Koolstra/Fix-a-drop_nlink-warning-in-minix_rename/20251103-022646
base: https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git vfs.all
patch link: https://lore.kernel.org/r/20251102182532.2442670-1-jkoolstra%40xs4all.nl
patch subject: [PATCH] Fix a drop_nlink warning in minix_rename
config: arm-randconfig-004-20251103 (https://download.01.org/0day-ci/archive/20251103/202511031556.5N9lmsZB-lkp@intel.com/config)
compiler: clang version 22.0.0git (https://github.com/llvm/llvm-project d2625a438020ad35330cda29c3def102c1687b1b)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251103/202511031556.5N9lmsZB-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202511031556.5N9lmsZB-lkp@intel.com/
All errors (new ones prefixed by >>):
>> fs/minix/namei.c:151:11: error: use of undeclared identifier 'EFSCORRUPTED'
151 | return -EFSCORRUPTED;
| ^~~~~~~~~~~~
fs/minix/namei.c:217:10: error: use of undeclared identifier 'EFSCORRUPTED'
217 | err = -EFSCORRUPTED;
| ^~~~~~~~~~~~
2 errors generated.
vim +/EFSCORRUPTED +151 fs/minix/namei.c
140
141 static int minix_unlink(struct inode * dir, struct dentry *dentry)
142 {
143 struct inode * inode = d_inode(dentry);
144 struct folio *folio;
145 struct minix_dir_entry * de;
146 int err;
147
148 if (inode->i_nlink < 1) {
149 printk(KERN_CRIT "minix-fs error: inode (ino: %ld) "
150 "has corrupted nlink", inode->i_ino);
> 151 return -EFSCORRUPTED;
152 }
153
154 de = minix_find_entry(dentry, &folio);
155 if (!de)
156 return -ENOENT;
157 err = minix_delete_entry(de, folio);
158 folio_release_kmap(folio, de);
159
160 if (err)
161 return err;
162 inode_set_ctime_to_ts(inode, inode_get_ctime(dir));
163 inode_dec_link_count(inode);
164 return 0;
165 }
166
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] Fix a drop_nlink warning in minix_rename
2025-11-02 18:25 [PATCH] Fix a drop_nlink warning in minix_rename Jori Koolstra
2025-11-03 4:42 ` kernel test robot
2025-11-03 7:58 ` kernel test robot
@ 2025-11-04 8:03 ` Jan Kara
2 siblings, 0 replies; 4+ messages in thread
From: Jan Kara @ 2025-11-04 8:03 UTC (permalink / raw)
To: Jori Koolstra
Cc: Christian Brauner, Tetsuo Handa, Taotao Chen, Jeff Layton,
Jan Kara, NeilBrown, linux-kernel, syzbot+a65e824272c5f741247d
On Sun 02-11-25 19:25:32, Jori Koolstra wrote:
> Syzbot found a drop_nlink warning that is triggered by an easy to
> detect nlink corruption. This patch adds sanity checks to minix_unlink
> and minix_rename to prevent the warning and instead return EFSCORRUPTED
> to the caller.
>
> The changes were tested using the syzbot reproducer as well as local
> testing.
>
> Signed-off-by: Jori Koolstra <jkoolstra@xs4all.nl>
> Reported-by: syzbot+a65e824272c5f741247d@syzkaller.appspotmail.com
> Closes: https://syzbot.org/bug?extid=a65e824272c5f741247d
Two comments below.
> ---
> fs/minix/namei.c | 13 +++++++++++++
> 1 file changed, 13 insertions(+)
>
> diff --git a/fs/minix/namei.c b/fs/minix/namei.c
> index a8d5a7e22b7b..4bc1d9c31284 100644
> --- a/fs/minix/namei.c
> +++ b/fs/minix/namei.c
> @@ -145,6 +145,12 @@ static int minix_unlink(struct inode * dir, struct dentry *dentry)
> struct minix_dir_entry * de;
> int err;
>
> + if (inode->i_nlink < 1) {
I guess it makes sense to check here for i_nlink == 0 for consistency.
> + printk(KERN_CRIT "minix-fs error: inode (ino: %ld) "
> + "has corrupted nlink", inode->i_ino);
> + return -EFSCORRUPTED;
> + }
> +
> de = minix_find_entry(dentry, &folio);
> if (!de)
> return -ENOENT;
> @@ -218,6 +224,13 @@ static int minix_rename(struct mnt_idmap *idmap,
> if (dir_de && !minix_empty_dir(new_inode))
> goto out_dir;
>
> + err = -EFSCORRUPTED;
> + if (new_inode->i_nlink == 0 || (dir_de && new_inode->i_nlink != 2)) {
> + printk(KERN_CRIT "minix-fs error: inode (ino: %ld) "
> + "has corrupted nlink", new_inode->i_ino);
> + goto out_dir;
> + }
> +
> err = -ENOENT;
> new_de = minix_find_entry(new_dentry, &new_folio);
> if (!new_de)
You should also check that 'old_dir' link count is correct. I.e.
if (dir_de && old_dir->i_nlink <= 2) {
error out.
}
Honza
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
^ permalink raw reply [flat|nested] 4+ messages in thread
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2025-11-04 8:03 ` Jan Kara
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