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

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.

Link: https://lkml.kernel.org/r/20230607161523.2876433-1-roberto.sassu@huaweicloud.com
Fixes: c3b1b1cbf002 ("ramfs: add support for "mode=" mount option")
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/fs/ramfs/inode.c b/fs/ramfs/inode.c
index 5ba580c78835fd8a85ce01f4c2f377f839220290..fef477c781073335e9c2c870436ce568d5ba4350 100644 (file)
--- 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 917528d102c4eb63b7e9d3ab7fae9a33d03e20cb..d506dc63dd47c5ff3d6f0961506a3e039d64b6ea 100644 (file)
--- 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 5e54ab5f61f2e620860efef3aaa68e784d402f68..c606ab89693a1dbd3897b959d972418c36730ec3 100644 (file)
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -4199,7 +4199,7 @@ 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,
 };