shmem: Use ramfs_kill_sb() for kill_sb method of ramfs-based tmpfs

[PATCH] shmem: Use ramfs_kill_sb() for kill_sb method of ramfs-based tmpfs

Posted by Roberto Sassu 2 years, 8 months ago

From: Roberto Sassu <roberto.sassu@huawei.com>

As the ramfs-based tmpfs uses ramfs_init_fs_context() for the
init_fs_context method, which allocates fc->s_fs_info, use ramfs_kill_sb()
to free it and avoid a memory leak.

Cc: stable@vger.kernel.org # v5.4.x
Fixes: f32356261d44 ("vfs: Convert ramfs, shmem, tmpfs, devtmpfs, rootfs to use the new mount API")
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
---
 fs/ramfs/inode.c      | 2 +-
 include/linux/ramfs.h | 1 +
 mm/shmem.c            | 2 +-
 3 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/ramfs/inode.c b/fs/ramfs/inode.c
index 5ba580c7883..fef477c7810 100644
--- a/fs/ramfs/inode.c
+++ b/fs/ramfs/inode.c
@@ -278,7 +278,7 @@ int ramfs_init_fs_context(struct fs_context *fc)
 	return 0;
 }
 
-static void ramfs_kill_sb(struct super_block *sb)
+void ramfs_kill_sb(struct super_block *sb)
 {
 	kfree(sb->s_fs_info);
 	kill_litter_super(sb);
diff --git a/include/linux/ramfs.h b/include/linux/ramfs.h
index 917528d102c..d506dc63dd4 100644
--- a/include/linux/ramfs.h
+++ b/include/linux/ramfs.h
@@ -7,6 +7,7 @@
 struct inode *ramfs_get_inode(struct super_block *sb, const struct inode *dir,
 	 umode_t mode, dev_t dev);
 extern int ramfs_init_fs_context(struct fs_context *fc);
+extern void ramfs_kill_sb(struct super_block *sb);
 
 #ifdef CONFIG_MMU
 static inline int
diff --git a/mm/shmem.c b/mm/shmem.c
index e40a08c5c6d..74abb97ea55 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -4196,7 +4196,7 @@ static struct file_system_type shmem_fs_type = {
 	.name		= "tmpfs",
 	.init_fs_context = ramfs_init_fs_context,
 	.parameters	= ramfs_fs_parameters,
-	.kill_sb	= kill_litter_super,
+	.kill_sb	= ramfs_kill_sb,
 	.fs_flags	= FS_USERNS_MOUNT,
 };
 
-- 
2.25.1

Re: [PATCH] shmem: Use ramfs_kill_sb() for kill_sb method of ramfs-based tmpfs

Posted by Andrew Morton 2 years, 8 months ago

(cc's added)

On Wed,  7 Jun 2023 18:15:23 +0200 Roberto Sassu <roberto.sassu@huaweicloud.com> wrote:

> From: Roberto Sassu <roberto.sassu@huawei.com>
> 
> As the ramfs-based tmpfs uses ramfs_init_fs_context() for the
> init_fs_context method, which allocates fc->s_fs_info, use ramfs_kill_sb()
> to free it and avoid a memory leak.
> 
> Cc: stable@vger.kernel.org # v5.4.x
> Fixes: f32356261d44 ("vfs: Convert ramfs, shmem, tmpfs, devtmpfs, rootfs to use the new mount API")
> Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
> ---
>  fs/ramfs/inode.c      | 2 +-
>  include/linux/ramfs.h | 1 +
>  mm/shmem.c            | 2 +-
>  3 files changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/ramfs/inode.c b/fs/ramfs/inode.c
> index 5ba580c7883..fef477c7810 100644
> --- a/fs/ramfs/inode.c
> +++ b/fs/ramfs/inode.c
> @@ -278,7 +278,7 @@ int ramfs_init_fs_context(struct fs_context *fc)
>  	return 0;
>  }
>  
> -static void ramfs_kill_sb(struct super_block *sb)
> +void ramfs_kill_sb(struct super_block *sb)
>  {
>  	kfree(sb->s_fs_info);
>  	kill_litter_super(sb);
> diff --git a/include/linux/ramfs.h b/include/linux/ramfs.h
> index 917528d102c..d506dc63dd4 100644
> --- a/include/linux/ramfs.h
> +++ b/include/linux/ramfs.h
> @@ -7,6 +7,7 @@
>  struct inode *ramfs_get_inode(struct super_block *sb, const struct inode *dir,
>  	 umode_t mode, dev_t dev);
>  extern int ramfs_init_fs_context(struct fs_context *fc);
> +extern void ramfs_kill_sb(struct super_block *sb);
>  
>  #ifdef CONFIG_MMU
>  static inline int
> diff --git a/mm/shmem.c b/mm/shmem.c
> index e40a08c5c6d..74abb97ea55 100644
> --- a/mm/shmem.c
> +++ b/mm/shmem.c
> @@ -4196,7 +4196,7 @@ static struct file_system_type shmem_fs_type = {
>  	.name		= "tmpfs",
>  	.init_fs_context = ramfs_init_fs_context,
>  	.parameters	= ramfs_fs_parameters,
> -	.kill_sb	= kill_litter_super,
> +	.kill_sb	= ramfs_kill_sb,
>  	.fs_flags	= FS_USERNS_MOUNT,
>  };
>  
> -- 
> 2.25.1

Re: [PATCH] shmem: Use ramfs_kill_sb() for kill_sb method of ramfs-based tmpfs

Posted by Roberto Sassu 2 years, 8 months ago

On 6/7/2023 7:43 PM, Andrew Morton wrote:
> (cc's added)

Ok. Recently, I started to automatize the recipients of the emails with 
a script that takes the output of get_maintainer.pl and takes only the 
maintainer, supporter and reviewer lines. Maybe I should add also 
blamed_fixes.

> On Wed,  7 Jun 2023 18:15:23 +0200 Roberto Sassu <roberto.sassu@huaweicloud.com> wrote:
> 
>> From: Roberto Sassu <roberto.sassu@huawei.com>
>>
>> As the ramfs-based tmpfs uses ramfs_init_fs_context() for the
>> init_fs_context method, which allocates fc->s_fs_info, use ramfs_kill_sb()
>> to free it and avoid a memory leak.
>>
>> Cc: stable@vger.kernel.org # v5.4.x
>> Fixes: f32356261d44 ("vfs: Convert ramfs, shmem, tmpfs, devtmpfs, rootfs to use the new mount API")

As I mentioned in the other thread, the correct Fixes tag is:

Fixes: c3b1b1cbf002 ("ramfs: add support for "mode=" mount option")

of course, if it can be modified at this stage.

Thanks

Roberto

>> Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
>> ---
>>   fs/ramfs/inode.c      | 2 +-
>>   include/linux/ramfs.h | 1 +
>>   mm/shmem.c            | 2 +-
>>   3 files changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/fs/ramfs/inode.c b/fs/ramfs/inode.c
>> index 5ba580c7883..fef477c7810 100644
>> --- a/fs/ramfs/inode.c
>> +++ b/fs/ramfs/inode.c
>> @@ -278,7 +278,7 @@ int ramfs_init_fs_context(struct fs_context *fc)
>>   	return 0;
>>   }
>>   
>> -static void ramfs_kill_sb(struct super_block *sb)
>> +void ramfs_kill_sb(struct super_block *sb)
>>   {
>>   	kfree(sb->s_fs_info);
>>   	kill_litter_super(sb);
>> diff --git a/include/linux/ramfs.h b/include/linux/ramfs.h
>> index 917528d102c..d506dc63dd4 100644
>> --- a/include/linux/ramfs.h
>> +++ b/include/linux/ramfs.h
>> @@ -7,6 +7,7 @@
>>   struct inode *ramfs_get_inode(struct super_block *sb, const struct inode *dir,
>>   	 umode_t mode, dev_t dev);
>>   extern int ramfs_init_fs_context(struct fs_context *fc);
>> +extern void ramfs_kill_sb(struct super_block *sb);
>>   
>>   #ifdef CONFIG_MMU
>>   static inline int
>> diff --git a/mm/shmem.c b/mm/shmem.c
>> index e40a08c5c6d..74abb97ea55 100644
>> --- a/mm/shmem.c
>> +++ b/mm/shmem.c
>> @@ -4196,7 +4196,7 @@ static struct file_system_type shmem_fs_type = {
>>   	.name		= "tmpfs",
>>   	.init_fs_context = ramfs_init_fs_context,
>>   	.parameters	= ramfs_fs_parameters,
>> -	.kill_sb	= kill_litter_super,
>> +	.kill_sb	= ramfs_kill_sb,
>>   	.fs_flags	= FS_USERNS_MOUNT,
>>   };
>>   
>> -- 
>> 2.25.1