Re: squid-3.HEAD IPAddress leak

Uhm, the kernel won't be free'ing userland memory at all; it doesn't give
a rats how its managed.

You're probably confused with the library - the libc is fumbling with
all the struct addrinfo things.

Also, if the bug bugs you, create a temporary pointer and pass that in. ;)

Adrian

On Fri, Feb 08, 2008, Amos Jeffries wrote:
> >
> > On Thu, 2008-02-07 at 12:21 +0900, Adrian Chadd wrote:
> >>
> >> Well, I haven't removed the temporary malloc/free pair, whatever its
> >> called;
> >> I've just removed Amos' workaround in src/comm.cc so it doesn't leak
> >> on my
> >> system whilst I profile.
> >>
> >> Still, this is one of those "death of a thousand cuts" method of
> >> killing performance..
> >
> > Right, I haven't seen the commit; care to mail the diff?
> >
>
>
> Here you go.
> "
> --- src/comm.cc 2008-01-19 20:50:42.000000000 +1300
> +++ src/comm.cc-2 2008-02-08 09:56:11.000000000 +1300
> @@ -1381,7 +1381,7 @@
>
> }
>
> -#ifdef _SQUID_LINUX_
> +#ifdef 0 // _SQUID_LINUX_
> /* 2007-11-27:
> * Linux Debian replaces our allocated AI pointer with garbage when
> * connect() fails. This leads to segmentation faults deallocating
> "
>
>
> In reply to your last few emails Adrian.
>
> re: can we join up on IRC?
>
> I may not be able to for the next few days, too much else on.
>
>
> re: Why are you trying to allocate the structure on invocation of
> GetAddrInfo() ?
>
> The design was to follow the well-known structure of the kernel call
> getaddrinfo(), which fills kernel-managed memory in a thread-safe way
> down a dynamic structure. The addrinfo structs are too nasty to use
> naked for anything like the amount of comm usage squid has. They are not
> an object per-se, but the root of a pointer tree to various types of
> node, which depend on the flags for their memory sizes.
> We could make a variant of the call which takes an addrinfo object and
> sets it up to point at the IPAddress internals correctly. BUT the bug we
> are looking at would then cause the IPAddress to become garbage, maybe
> have the kernel free'ing stack memory, etc.
>
>
> re: Argh, this temporary malloc/free pair is peppered throughout the
> codebase! Grr.
>
> You already know there are naked comm calls everywhere. :-( Most of them
> calls addrinfo was desgined for use in.
>
>
> re: I've removed that hack, and things work fine for me. Ubuntu 7.01 here,
> x86_64.
>
> Yes, I found no problem on ubuntu also. I simply could not (after very
> little searching) find a #if test that would only work for Debian.
>
>
> Amos
>

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