Coccinelle: understanding its output

["Fabio M. De Francesco" <fmdefrancesco@gmail.com>]

I think that I don't yet understand Coccinelle's output. 

I've just run the following command:
spatch --sp-file scripts/coccinelle/free/kfree.cocci --dir drivers/staging/
wlan-ng/prism2fw.c

It outputs something that looks like a patch:

HANDLING: drivers/staging/wlan-ng/prism2fw.c
     (ONCE) already tagged but only removed, so safe
diff = 
--- drivers/staging/wlan-ng/prism2fw.c
+++ /tmp/cocci-output-17844-0c6c7c-prism2fw.c

First, what is /tmp/cocci-output-17844-0c6c7c-prism2fwc? It is not a file in /
tmp. If it is a file, where is it?

The output goes on with lines like the following ones:

  @@ -1008,8 +1005,6 @@ static int writeimage(struct wlandevice
        rstmsg = kzalloc(sizeof(*rstmsg), GFP_KERNEL);
        rwrmsg = kzalloc(sizeof(*rwrmsg), GFP_KERNEL);
        if (!rstmsg || !rwrmsg) {
-               kfree(rstmsg);
-               kfree(rwrmsg);
                netdev_err(wlandev->netdev,
                           "%s: no memory for firmware download, aborting 
download\n",
                           __func__);

Please read the two lines with a trailing '-'... Does Coccinelle mean that 
they should be removed? If yes, I'm not able to understand why, because I 
think they must not be removed. Am I wrong?

 I'd appreciate some help.

Thanks,

Fabio