Re: [patch 2.6.12-rc1-mm4] fork_connector: add a fork connector

[Evgeniy Polyakov <johnpol@2ka.mipt.ru>]

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On Thu, 2005-04-07 at 15:47 -0700, Jay Lan wrote:
> BTW, when it happened last time, my program listening to the socket
> complained about duplicate messages received.
> 
>     Unmatched seq. Rcvd=1824062, expected=1824061   <===
>     Unmatched seq. Rcvd=1824062, expected=1824063   <===
>     Unmatched seq. Rcvd=1824348, expected=1824307
> 
> When my program received 1824062 while expecting 1824061
> it adjusted itself to expect the next one being 1824063. But instead
> the message of 1824062 arrived the second time.

Thank you for your report.

Could you reproduce a bug with the attached patch?

>     - jay


* looking for johnpol@2ka.mipt.ru-2004/connector--main--0--patch-38 to compare with
* comparing to johnpol@2ka.mipt.ru-2004/connector--main--0--patch-38
M  connector.c

* modified files

--- orig/drivers/connector/connector.c
+++ mod/drivers/connector/connector.c
@@ -121,7 +121,7 @@
 	NETLINK_CB(skb).dst_groups = groups;
 
 	uskb = skb_clone(skb, GFP_ATOMIC);
-	if (uskb)
+	if (uskb && 0)
 		netlink_unicast(dev->nls, uskb, 0, 0);
 	
 	netlink_broadcast(dev->nls, skb, 0, groups, GFP_ATOMIC);
@@ -158,7 +158,7 @@
 	}
 	spin_unlock_bh(&dev->cbdev->queue_lock);
 
-	return found;
+	return (found)?0:-ENODEV;
 }
 
 /*
@@ -181,7 +181,6 @@
 				"requested msg->len=%u[%u], nlh->nlmsg_len=%u, skb->len=%u.\n",
 				msg->len, NLMSG_SPACE(msg->len + sizeof(*msg)),
 				nlh->nlmsg_len, skb->len);
-		kfree_skb(skb);
 		return -EINVAL;
 	}
 #if 0
@@ -215,17 +214,18 @@
 	       skb->len, skb->data_len, skb->truesize, skb->protocol,
 	       skb_cloned(skb), skb_shared(skb));
 #endif
-	while (skb->len >= NLMSG_SPACE(0)) {
+	if (skb->len >= NLMSG_SPACE(0)) {
 		nlh = (struct nlmsghdr *)skb->data;
+
 		if (nlh->nlmsg_len < sizeof(struct cn_msg) ||
 		    skb->len < nlh->nlmsg_len ||
 		    nlh->nlmsg_len > CONNECTOR_MAX_MSG_SIZE) {
-#if 0
+#if 1
 			printk(KERN_INFO "nlmsg_len=%u, sizeof(*nlh)=%u\n",
 			       nlh->nlmsg_len, sizeof(*nlh));
 #endif
 			kfree_skb(skb);
-			break;
+			goto out;
 		}
 
 		len = NLMSG_ALIGN(nlh->nlmsg_len);
@@ -233,22 +233,11 @@
 			len = skb->len;
 
 		err = __cn_rx_skb(skb, nlh);
-		if (err) {
-#if 0
-			if (err < 0 && (nlh->nlmsg_flags & NLM_F_ACK))
-				netlink_ack(skb, nlh, -err);
-#endif
-			break;
-		} else {
-#if 0
-			if (nlh->nlmsg_flags & NLM_F_ACK)
-				netlink_ack(skb, nlh, 0);
-#endif
-			break;
-		}
-		skb_pull(skb, len);
+		if (err < 0)
+			kfree_skb(skb);
 	}
-			
+
+out:
 	kfree_skb(__skb);
 }
 





-- 
        Evgeniy Polyakov

Crash is better than data corruption -- Arthur Grabowski

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