[Devel] Re: [PATCH] struct file leakage

[Eric W. Biederman]

Kirill Korotaev <dev at sw.ru> writes:

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

Or something the intent or the filp holds a reference to?

Looks like this has been broken since 834f2a4a1554dc5b2598038b3fe8703defcbe467
about 9 months ago.

The patch looks sane.

Trond did you just miss this case?


> Signed-Off-By: Alexey Kuznetsov <kuznet at ms2.inr.ac.ru>
> CC: Kirill Korotaev <dev at 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;

Eric