[NETLINK]: Don't BUG on undersized allocations
Currently netlink users BUG when the allocated skb for an event
notification is undersized. While this is certainly a kernel bug,
its not critical and crashing the kernel is too drastic, especially
when considering that these errors have appeared multiple times in
the past and it BUGs even if no listeners are present.
This patch replaces BUG by WARN_ON and changes the notification
functions to inform potential listeners of undersized allocations
using a unique error code (EMSGSIZE).
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index e76539a..9bf9ae0 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -320,7 +320,7 @@
nlh = nlmsg_put(skb, pid, seq, type, sizeof(*ifm), flags);
if (nlh == NULL)
- return -ENOBUFS;
+ return -EMSGSIZE;
ifm = nlmsg_data(nlh);
ifm->ifi_family = AF_UNSPEC;
@@ -384,7 +384,8 @@
return nlmsg_end(skb, nlh);
nla_put_failure:
- return nlmsg_cancel(skb, nlh);
+ nlmsg_cancel(skb, nlh);
+ return -EMSGSIZE;
}
static int rtnl_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb)
@@ -633,9 +634,12 @@
err = rtnl_fill_ifinfo(nskb, dev, iw, iw_buf_len, RTM_NEWLINK,
NETLINK_CB(skb).pid, nlh->nlmsg_seq, 0, 0);
- /* failure impilies BUG in if_nlmsg_size or wireless_rtnetlink_get */
- BUG_ON(err < 0);
-
+ if (err < 0) {
+ /* -EMSGSIZE implies BUG in if_nlmsg_size */
+ WARN_ON(err == -EMSGSIZE);
+ kfree_skb(nskb);
+ goto errout;
+ }
err = rtnl_unicast(nskb, NETLINK_CB(skb).pid);
errout:
kfree(iw_buf);
@@ -678,9 +682,12 @@
goto errout;
err = rtnl_fill_ifinfo(skb, dev, NULL, 0, type, 0, 0, change, 0);
- /* failure implies BUG in if_nlmsg_size() */
- BUG_ON(err < 0);
-
+ if (err < 0) {
+ /* -EMSGSIZE implies BUG in if_nlmsg_size() */
+ WARN_ON(err == -EMSGSIZE);
+ kfree_skb(skb);
+ goto errout;
+ }
err = rtnl_notify(skb, 0, RTNLGRP_LINK, NULL, GFP_KERNEL);
errout:
if (err < 0)