cifs: protect session status check in smb2_reconnect()

Use @ses->ses_lock to protect access of @ses->ses_status.

Cc: stable@vger.kernel.org
Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

Author: Paulo Alcantara

fs/cifs/smb2pdu.c

@@ -175,8 +175,17 @@ smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon,
 		}
 	}
 	spin_unlock(&tcon->tc_lock);
-	if ((!tcon->ses) || (tcon->ses->ses_status == SES_EXITING) ||
-	    (!tcon->ses->server) || !server)
+
+	ses = tcon->ses;
+	if (!ses)
+		return -EIO;
+	spin_lock(&ses->ses_lock);
+	if (ses->ses_status == SES_EXITING) {
+		spin_unlock(&ses->ses_lock);
+		return -EIO;
+	}
+	spin_unlock(&ses->ses_lock);
+	if (!ses->server || !server)
 		return -EIO;
 
 	spin_lock(&server->srv_lock);
@@ -204,8 +213,6 @@ smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon,
 	if (rc)
 		return rc;
 
-	ses = tcon->ses;
-
 	spin_lock(&ses->chan_lock);
 	if (!cifs_chan_needs_reconnect(ses, server) && !tcon->need_reconnect) {
 		spin_unlock(&ses->chan_lock);