Re: [Powertop] Device list sort function bug

[Chris Ferron <chris.e.ferron at linux.intel.com>]

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On 07/10/2012 11:11 PM, Igor Zhbanov wrote:
> Hello!
>
> 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<-------------------------------------------------------------------------- 
>
>
> Thank you.
>
>
>
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Your patch has been merged.
Thank you,