Memory Leak in Thread Cleanup (jemalloc 4.0.4)

[Jason Evans]

On Feb 11, 2016, at 2:33 PM, Christopher Ferris <cferris at google.com> wrote:
> It appears, that under certain circumstances, the arenas_cache can be leaked when shutting down a thread.
> 
> Specifically, in tsd.c (function tsd_cleanup), this code:
> 
> #define O(n, t)                                                         \
>                 n##_cleanup(tsd);
> MALLOC_TSD
> #undef O
>                 tsd->state = tsd_state_purgatory;
>                 tsd_set(tsd);
>                 break;
> 
> 
> The cleanup part can wind up creating an arenas_cache, then the tsd_set clears the arenas_cache pointer, and the memory is leaked away.
> 
> I added this call:
> 
>                 arenas_cache_cleanup(tsd_get());
> 
> After the undef and before the tsd->state, and the leak disappears. I'm not sure if there is a better way to fix this though.
> 

Fix integrated:

	https://github.com/jemalloc/jemalloc/commit/39f58755a7c2c5c12c9b732c17fe472c9872ab4b

Thanks,
Jason