[PATCH 6.4 742/800] shmem: use ramfs_kill_sb() for kill_sb method of ramfs-based tmpfs

Greg Kroah-Hartman
2023-07-16T20:27:35Z

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

commit 36ce9d76b0a93bae799e27e4f5ac35478c676592 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/ramfs/inode.c | 2 +-
include/linux/ramfs.h | 1 +
mm/shmem.c | 2 +-
3 files changed, 3 insertions(+), 2 deletions(-)

--- a/fs/ramfs/inode.c
+++ b/fs/ramfs/inode.c
@@ -278,7 +278,7 @@ int ramfs_init_fs_context(struct fs_cont
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);
--- 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
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -4196,7 +4196,7 @@ static struct file_system_type shmem_fs_
.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,
};