Re: bug in SlabAlloc / VALGRIND_MAKE_MEM_DEFINED - Mailing list pgsql-hackers

On 04/04/2017 10:42 PM, Tomas Vondra wrote:
> Hi,
>
> Andres nagged to me about valgrind runs taking much longer since
> 9fab40ad introduced the SlabContext into reorderbuffer.c. And by
> "longer" I mean hours instead of minutes.
>
> After a bit of investigation I stumbled on this line in slab.c:
>
>   VALGRIND_MAKE_MEM_DEFINED(chunk, SlabChunkGetPointer(chunk));
>
> which is wrong, because the second parameter should be size and not
> another pointer. This essentially marks a lot of memory as defined,
> which results in the extreme test runtime.
>
> Instead, the line should be:
>
>   VALGRIND_MAKE_MEM_DEFINED(SlabChunkGetPointer(chunk), sizeof(int32));
>
> Patch attached.
>

Turns out SlabCheck() was missing VALGRIND_MAKE_MEM_DEFINED, resulting 
in a valgrind failure with --enable-assert. Updated patch version 
attached, passing all tests in test_decoding.

regards

-- 
Tomas Vondra                  http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services