device driver memory leak in 5.1-20030726?

[John-Mark Gurney]

Lukas Ertl wrote this message on Mon, Jul 28, 2003 at 01:11 +0200:
> On Sun, 27 Jul 2003, John-Mark Gurney wrote:
> Then I have no explanation.  I'm running the box with a WiFi card,
> generating lots of network traffic, and the box is running fine, no
> panics, and low devbuf allocation.  I'm running the box with the USB
> Bluetooth dongle, generating much less traffic (it's just a 9.6kbit GSM
> link), and the box panics within half an hour in kmem_malloc, with devbuf
> allocation up to 74MB.  It must be either in the Bluetooth code or in the
> USB code.

Hmm. this is wierd, it appears to be a bug in the Netgraph code.  There
is a bit of code that allocates memory for the data, and then promptly
overwrites the malloc w/ data from the mbuf.

Try the attached patch.  This could VERY well crash your machine as I
don't know mbuf code very well.

Thanks.

-- 
  John-Mark Gurney				Voice: +1 415 225 5579

     "All that I will do, has been done, All that I have, has not."
-------------- next part --------------
Index: ng_device.c
===================================================================
RCS file: /home/ncvs/src/sys/netgraph/ng_device.c,v
retrieving revision 1.3
diff -u -u -r1.3 ng_device.c
--- ng_device.c	3 Mar 2003 12:15:52 -0000	1.3
+++ ng_device.c	28 Jul 2003 00:47:30 -0000
@@ -360,12 +360,6 @@
 		return(-1);
 	}
 
-	buffer = malloc(sizeof(char)*m->m_len, M_DEVBUF, M_NOWAIT | M_ZERO);
-	if(buffer == NULL) {
-		printf("%s(): ERROR: buffer malloc failed\n",__func__);
-		return(-1);
-	}
-
 	buffer = mtod(m,char *);
 
 	if( (connection->loc+m->m_len) < NGD_QUEUE_SIZE) {
@@ -374,7 +368,8 @@
 	} else
 		printf("%s(): queue full, first read out a bit\n",__func__);
 
-	free(buffer,M_DEVBUF);
+	/* XXX - free chain? */
+	m_free(m);
 
 	return(0);
 }