[Buildroot] [PATCH] busybox: disable CONFIG_FEATURE_CLEAN_UP in default configs

[Thomas Petazzoni <thomas.petazzoni@free-electrons.com>]

Hello,

On Wed,  5 Jul 2017 11:34:54 +0200, Peter Korsgaard wrote:
> FEATURE_CLEAN_UP is a configuration feature to get busybox to explicitly
> call free() on dynamic allocated memory just before exiting so memory leak
> detectors like valgrind don't get confused.  Upstream explicitly recommends
> to NOT enable this option:
> 
> config FEATURE_CLEAN_UP
> 	bool "Clean up all memory before exiting (usually not needed)"
> 	default n
> 	help
> 	  As a size optimization, busybox normally exits without explicitly
> 	  freeing dynamically allocated memory or closing files. This saves
> 	  space since the OS will clean up for us, but it can confuse debuggers
> 	  like valgrind, which report tons of memory and resource leaks.
> 
> 	  Don't enable this unless you have a really good reason to clean
> 	  things up manually.
> 
> Having this option enabled adds a bit of bloat, but more significantly these
> cleanup code paths don't get tested very often so some times get out of sync
> with the allocation code which can lead to crashes (or security issues from
> double frees), so it is safer to disable the option.
> 
> For people wanting to debug memory leak issues with busybox, the option can
> still be enabled with a configuration fragment (or a custom config).
> 
> The size difference isn't huge (br-arm-full-static):
> 
> -rwxr-xr-x 1 peko peko 886K Jul  5 10:56 output-busybox1/target/bin/busybox
> -rwxr-xr-x 1 peko peko 882K Jul  5 10:53 output-busybox2/target/bin/busybox
> 
> Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
> ---
>  package/busybox/busybox-minimal.config | 2 +-
>  package/busybox/busybox.config         | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)

Applied to master, thanks.

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com