Date: Fri, 19 Aug 2005 21:43:43 +0400 From: Roman Kurakin <rik@cronyx.ru> To: David Vos <david.vos@gmail.com> Cc: freebsd-net@freebsd.org Subject: Re: netgraph memory trouble Message-ID: <43061A4F.4050206@cronyx.ru> In-Reply-To: <16e39c5105081814432e922ec4@mail.gmail.com> References: <16e39c5105081814432e922ec4@mail.gmail.com>
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It seems reasonable. If no one take care of it, let me know
I'll commit it.
rik
David Vos wrote:
>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)
>{
> const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
> int error = 0;
>
> if (hook == priv->out) {
> printf("ng_split: got packet from out hook!\n");
> NG_FREE_ITEM(item);
> error = EINVAL;
> } else if ((hook == priv->in) && (priv->mixed != NULL)) {
> NG_FWD_ITEM_HOOK(error, item, priv->mixed);
> } else if ((hook == priv->mixed) && (priv->out != NULL)) {
> NG_FWD_ITEM_HOOK(error, item, priv->out);
> }
>
> return (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=%x, priv->in=%x, priv->out=%x
> priv->mixed=%x\n", hook, priv->in, priv->out, priv->mixed);
>
> if (hook == priv->out) {
> printf("ng_split: got packet from out hook!\n");
> NG_FREE_ITEM(item);
> error = EINVAL;
> } else if ((hook == priv->in) && (priv->mixed != NULL)) {
> NG_FWD_ITEM_HOOK(error, item, priv->mixed);
> } else if ((hook == priv->mixed) && (priv->out != 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 = EINVAL;
> }
>
>In /var/log/messages, I get:
>Aug 18 15:31:50 foo kernel: ng_split: got packet hook=c53f6800,
>priv->in=c53f6800, priv->out=c53f8c80 priv->mixed=0
>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
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>
>
>
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