+ shmem-use-ramfs_kill_sb-for-kill_sb-method-of-ramfs-based-tmpfs.patch added to mm-unstable branch

+ shmem-use-ramfs_kill_sb-for-kill_sb-method-of-ramfs-based-tmpfs.patch added to mm-unstable branch

[Andrew Morton]

The patch titled
     Subject: shmem: use ramfs_kill_sb() for kill_sb method of ramfs-based tmpfs
has been added to the -mm mm-unstable branch.  Its filename is
     shmem-use-ramfs_kill_sb-for-kill_sb-method-of-ramfs-based-tmpfs.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/shmem-use-ramfs_kill_sb-for-kill_sb-method-of-ramfs-based-tmpfs.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Before you just go and hit "reply", please:
   a) Consider who else should be cc'ed
   b) Prefer to cc a suitable mailing list as well
   c) Ideally: find the original patch on the mailing list and do a
      reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days

------------------------------------------------------
From: Roberto Sassu <roberto.sassu@huawei.com>
Subject: shmem: use ramfs_kill_sb() for kill_sb method of ramfs-based tmpfs
Date: Wed, 7 Jun 2023 18:15:23 +0200

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: f32356261d44 ("vfs: Convert ramfs, shmem, tmpfs, devtmpfs, rootfs to use the new mount API")
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>
---

 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~shmem-use-ramfs_kill_sb-for-kill_sb-method-of-ramfs-based-tmpfs
+++ a/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~shmem-use-ramfs_kill_sb-for-kill_sb-method-of-ramfs-based-tmpfs
+++ a/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~shmem-use-ramfs_kill_sb-for-kill_sb-method-of-ramfs-based-tmpfs
+++ a/mm/shmem.c
@@ -4214,7 +4214,7 @@ 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,
 };
 
_

Patches currently in -mm which might be from roberto.sassu@huawei.com are

memfd-check-for-non-null-file_seals-in-memfd_create-syscall.patch
shmem-use-ramfs_kill_sb-for-kill_sb-method-of-ramfs-based-tmpfs.patch