smb3: missing lock when picking channel

commit 8094a600245e9b28eb36a13036f202ad67c1f887 upstream.

Coverity spotted a place where we should have been holding the
channel lock when accessing the ses channel index.

Addresses-Coverity: 1582039 ("Data race condition (MISSING_LOCK)")
Cc: stable@vger.kernel.org
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/smb/client/transport.c b/fs/smb/client/transport.c
index 994d70193432978de213a19a0f9933bd90e63671..e1a79e031b28ccc85571720bc0510c219bc8daef 100644 (file)
--- a/fs/smb/client/transport.c
+++ b/fs/smb/client/transport.c
@@ -1057,9 +1057,11 @@ struct TCP_Server_Info *cifs_pick_channel(struct cifs_ses *ses)
                index = (uint)atomic_inc_return(&ses->chan_seq);
                index %= ses->chan_count;
        }
+
+       server = ses->chans[index].server;
        spin_unlock(&ses->chan_lock);
 
-       return ses->chans[index].server;
+       return server;
 }
 
 int