Re: [Powertop] Device list sort function bug

Dear Igor,


thank you for your patches!


Am Mittwoch, den 11.07.2012, 10:11 +0400 schrieb Igor Zhbanov:

> Sometimes PowerTOP dies with a Segmentation Fault while generating
> the report. Little investigation shown that it dies while sorting
> the device list. The problem is that comparison function devlist_sort
> is incorrect.
> 
> The function should return true if first argument "preceeds" second.
> But when strcmp() is used, it can return -1, 0 and 1. So both -1 and 1
> values are silently converted to true, which is wrong. It confuses the sort()
> function and it crosses boundary of array.
> 
> Here is the patch:
> --8<--Cut-here----------------------------------------------------------------
> diff -purN powertop-il/src/devlist.cpp powertop-il-fix/src/devlist.cpp
> --- powertop-il/src/devlist.cpp	2012-07-03 17:00:50.000000000 +0400
> +++ powertop-il-fix/src/devlist.cpp	2012-07-03 20:01:05.896232845 +0400
> @@ -273,7 +273,7 @@ static bool devlist_sort(struct devuser
>   	if (i->pid != j->pid)
>   		return i->pid<  j->pid;
> 
> -	return strcmp(i->device, j->device);
> +	return (strcmp(i->device, j->device)<  0);
>   }
> 
>   static const char *dev_class(int line)
> --8<--------------------------------------------------------------------------

Nice find!

To decrease work for the maintainers, could you please send patches
formatted by `git format-patch`? After that you can either use `git
send-email` or copy the output into Seamonkey’s new message window.

        $ git clone git://github.com/fenrus75/powertop.git
        $ cd powertop
        $ git config --global user.name "Igor Zhbanov"
        $ git config --global user.email i.zhbanov(a)samsung.com
        $ git checkout -b sort-fix # new branch for each fix
        $ # apply your change
        $ git commit -a # enter a nice commit message \
        you should be able to use your great ones from your messages
        $ git format-patch -1

Then maintainers can just apply it using the following command.

    $ git am yourmessagewithpatch.mbox

If you need more help with Git, just ask.


Thanks,

Paul

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