From: Steve French <stfrench@microsoft.com>
Date: Fri, 24 Sep 2021 00:18:37 +0000 (-0500)
Subject: cifs: fix incorrect check for null pointer in header_assemble
X-Git-Tag: accepted/tizen/unified/20230118.172025~6285^2
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=9ed38fd4a15417cac83967360cf20b853bfab9b6;p=platform%2Fkernel%2Flinux-rpi.git

cifs: fix incorrect check for null pointer in header_assemble

Although very unlikely that the tlink pointer would be null in this case,
get_next_mid function can in theory return null (but not an error)
so need to check for null (not for IS_ERR, which can not be returned
here).

Address warning:

        fs/smbfs_client/connect.c:2392 cifs_match_super()
        warn: 'tlink' isn't an ERR_PTR

Pointed out by Dan Carpenter via smatch code analysis tool

CC: stable@vger.kernel.org
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
---

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 7881115..c3b94c1 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -2389,9 +2389,10 @@ cifs_match_super(struct super_block *sb, void *data)
 	spin_lock(&cifs_tcp_ses_lock);
 	cifs_sb = CIFS_SB(sb);
 	tlink = cifs_get_tlink(cifs_sb_master_tlink(cifs_sb));
-	if (IS_ERR(tlink)) {
+	if (tlink == NULL) {
+		/* can not match superblock if tlink were ever null */
 		spin_unlock(&cifs_tcp_ses_lock);
-		return rc;
+		return 0;
 	}
 	tcon = tlink_tcon(tlink);
 	ses = tcon->ses;