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

Evgeniy Polyakov
2005-04-08T10:21:52Z

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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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