Re: [Xen-devel] Libxenstore memory leak on static compile

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Wed, 2012-09-12 at 14:44 +0100, Andres Lagar-Cavilla wrote:
> When statically compiling libxenstore.a, the USE_PTHREAD define is not
> applied. This results in cleanup_{pus/pop} being no-ops. cleanup_p*
> are used throughout xs.c:read_message to free malloc'ed objects.
> 
> In short, libxenstore.a will leak memory when reading xenstore
> messages. OOM killer awaits.
> 
> This could be solved by either turning on USE_PTHREAD for .a
> compilation (which, N.B. will not actually link libpthread but instead
> produce an object archive that needs to be eventually linked to
> libpthread.so), or by replacing cleanup_p* by proper free calls.

The reason for the non-pthreads static library was so that you could
build tiny statically linked xenstore clients against tiny libcs (like
uclibc) to have things small enough to fit in e.g. your installer initrd
or in your "guest tools" package.

It used to be that uclibc didn't have a pthreads library.  Maybe this
has changed though (Roger, CCd, would know).

We don't seem to use pthread_cleanup_push/pop very extensively, so I
think using proper free calls is probably the way to go?

Using that pthread facility as a cheap and nasty GC seems a bit wrong to
me anyhow.

Ian.


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