cifs: cifs_chan_is_iface_active should be called with chan_lock held

cifs_chan_is_iface_active checks the channels of a session to see
if the associated iface is active. This should always happen
with chan_lock held. However, these two callers of this function
were missing this locking.

This change makes sure the function calls are protected with
proper locking.

Fixes: b54034a ("cifs: during reconnect, update interface if necessary")
Fixes: fa1d050 ("cifs: account for primary channel in the interface list")
Cc: stable@vger.kernel.org
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

Author: sprasad-microsoft

fs/smb/client/connect.c

@@ -232,10 +232,13 @@ cifs_mark_tcp_ses_conns_for_reconnect(struct TCP_Server_Info *server,
 	spin_lock(&cifs_tcp_ses_lock);
 	list_for_each_entry_safe(ses, nses, &pserver->smb_ses_list, smb_ses_list) {
 		/* check if iface is still active */
-		if (!cifs_chan_is_iface_active(ses, server))
+		spin_lock(&ses->chan_lock);
+		if (!cifs_chan_is_iface_active(ses, server)) {
+			spin_unlock(&ses->chan_lock);
 			cifs_chan_update_iface(ses, server);
+			spin_lock(&ses->chan_lock);
+		}
 
-		spin_lock(&ses->chan_lock);
 		if (!mark_smb_session && cifs_chan_needs_reconnect(ses, server)) {
 			spin_unlock(&ses->chan_lock);
 			continue;

fs/smb/client/smb2ops.c

@@ -784,9 +784,14 @@ SMB3_request_interfaces(const unsigned int xid, struct cifs_tcon *tcon, bool in_
 		goto out;
 
 	/* check if iface is still active */
+	spin_lock(&ses->chan_lock);
 	pserver = ses->chans[0].server;
-	if (pserver && !cifs_chan_is_iface_active(ses, pserver))
+	if (pserver && !cifs_chan_is_iface_active(ses, pserver)) {
+		spin_unlock(&ses->chan_lock);
 		cifs_chan_update_iface(ses, pserver);
+		spin_lock(&ses->chan_lock);
+	}
+	spin_unlock(&ses->chan_lock);
 
 out:
 	kfree(out_buf);