Date: Thu, 18 Aug 2005 15:43:32 -0600 From: David Vos <david.vos@gmail.com> To: freebsd-net@freebsd.org Subject: netgraph memory trouble Message-ID: <16e39c5105081814432e922ec4@mail.gmail.com>
next in thread | raw e-mail | index | archive | help
I have been playing with the netgraph ng_split node. I discovered
that if I sent packets to it, after a period of time, I could no
longer use netgraph. If I tried to use ngctl, I got an error back
saying that it could not allocate memory to send a message. This also
meant that I could not shutdown my nodes (because that required
sending a message) and had to reboot my machine to start using
netgraph again.
vmstat -m would show netgraph_item having 128 items in use.
I am sending data to the split node using the macro
"NG_FWD_ITEM_HOOK". Since this macro nulls out the item pointer, I
assume it takes full responsibility to free the item if something
fails.
The item then gets sent on to the function:
static int
ng_split_rcvdata(hook_p hook, item_p item)
{
=09const priv_p=09priv =3D NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
=09int=09=09error =3D 0;
=09if (hook =3D=3D priv->out) {
=09=09printf("ng_split: got packet from out hook!\n");
=09=09NG_FREE_ITEM(item);
=09=09error =3D EINVAL;
=09} else if ((hook =3D=3D priv->in) && (priv->mixed !=3D NULL)) {
=09=09NG_FWD_ITEM_HOOK(error, item, priv->mixed);
=09} else if ((hook =3D=3D priv->mixed) && (priv->out !=3D NULL)) {
=09=09NG_FWD_ITEM_HOOK(error, item, priv->out);
=09}
=09return (error);
}
Unfortunately, if priv->mixed or priv->out are NULL, then there is no
error generated, and the item is not freed.
I modified the function to be:
printf("ng_split: got packet hook=3D%x, priv->in=3D%x, priv->out=3D=
%x
priv->mixed=3D%x\n", hook, priv->in, priv->out, priv->mi=
xed);
if (hook =3D=3D priv->out) {
printf("ng_split: got packet from out hook!\n");
NG_FREE_ITEM(item);
error =3D EINVAL;
} else if ((hook =3D=3D priv->in) && (priv->mixed !=3D NULL)) {
NG_FWD_ITEM_HOOK(error, item, priv->mixed);
} else if ((hook =3D=3D priv->mixed) && (priv->out !=3D NULL)) {
NG_FWD_ITEM_HOOK(error, item, priv->out);
} else {
printf("ng_split: got packet from unknown hook, or
output hook is null\n");
NG_FREE_ITEM(item);
error =3D EINVAL;
}
In /var/log/messages, I get:
Aug 18 15:31:50 foo kernel: ng_split: got packet hook=3Dc53f6800,
priv->in=3Dc53f6800, priv->out=3Dc53f8c80 priv->mixed=3D0
Aug 18 15:31:50 foo kernel: ng_split: got packet from unknown hook, or
output hook is null
After making this modification to the code, I have not experienced any
of the memory problems mentioned above.
My conclusion is that an else clause needs to be added to the branches
in the ng_split_rcfdata() function.
I am using FreeBSD 5.4-RELEASE #1.
David
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?16e39c5105081814432e922ec4>