[PATCH 5.17 030/772] cifs: fix potential double free during failed mount

[Greg Kroah-Hartman]

From: Ronnie Sahlberg <lsahlber@xxxxxxxxxx>

commit 8378a51e3f8140f60901fb27208cc7a6e47047b5 upstream.

RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=2088799

Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Roberto Bergantinos <rbergant@xxxxxxxxxx>
Signed-off-by: Ronnie Sahlberg <lsahlber@xxxxxxxxxx>
Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 fs/cifs/cifsfs.c |   10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -836,7 +836,7 @@ cifs_smb3_do_mount(struct file_system_ty
 	      int flags, struct smb3_fs_context *old_ctx)
 {
 	int rc;
-	struct super_block *sb;
+	struct super_block *sb = NULL;
 	struct cifs_sb_info *cifs_sb = NULL;
 	struct cifs_mnt_data mnt_data;
 	struct dentry *root;
@@ -932,9 +932,11 @@ out_super:
 	return root;
 out:
 	if (cifs_sb) {
-		kfree(cifs_sb->prepath);
-		smb3_cleanup_fs_context(cifs_sb->ctx);
-		kfree(cifs_sb);
+		if (!sb || IS_ERR(sb)) {  /* otherwise kill_sb will handle */
+			kfree(cifs_sb->prepath);
+			smb3_cleanup_fs_context(cifs_sb->ctx);
+			kfree(cifs_sb);
+		}
 	}
 	return root;
 }