Re: [PATCH] struct file leakage

Andrew Morton
2006-07-10T10:06:31Z

On Mon, 10 Jul 2006 13:05:35 +0400
Kirill Korotaev <dev@sw.ru> wrote:

> Hello!
>
> Andrew, this is a patch from Alexey Kuznetsov for 2.6.16.
> I believe 2.6.17 still has this leak.
>
> -------------------------------------------------------------
>
> 2.6.16 leaks like hell. While testing, I found massive leakage
> (reproduced in openvz) in:
>
> *filp
> *size-4096
>
> And 1 object leaks in
> *size-32
> *size-64
> *size-128
>
>
> It is the fix for the first one. filp leaks in the bowels
> of namei.c.
>
> Seems, size-4096 is file table leaking in expand_fdtables.

I suspect that's been there for a long time.

> I have no idea what are the rest and why they show only
> accompaniing another leaks. Some debugging structs?

I don't understand this. Are you implying that there are other bugs.

> Signed-Off-By: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
> CC: Kirill Korotaev <dev@openvz.org>
>

> --- linux-2.6.16-w/fs/namei.c 2006-07-10 11:43:11.000000000 +0400
> +++ linux-2.6.16/fs/namei.c 2006-07-10 11:53:36.000000000 +0400
> @@ -1774,8 +1774,15 @@ do_link:
> if (error)
> goto exit_dput;
> error = __do_follow_link(&path, nd);
> - if (error)
> + if (error) {
> + /* Does someone understand code flow here? Or it is only
> + * me so stupid? Anathema to whoever designed this non-sense
> + * with "intent.open".
> + */
> + if (!IS_ERR(nd->intent.open.file))
> + release_open_intent(nd);
> return error;
> + }
> nd->flags &= ~LOOKUP_PARENT;
> if (nd->last_type == LAST_BIND)
> goto ok;
>

It's good to have some more Alexeycomments in the tree.

I wonder if we're also needing a path_release() here. And if not, whether
it is still safe to run release_open_intent() against this nameidata?

Hopefully Trond can recall what's going on in there...