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

[Roberto Sassu]

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@xxxxxxxxxxxxxxx> wrote:
>
> > From: Roberto Sassu <roberto.sassu@xxxxxxxxxx>
> >
> > 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@xxxxxxxxxxxxxxx # 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@xxxxxxxxxx>
> > ---
> >   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