Re: Please pull my perf.git urgent branch

From: Kumar Gala
Date: Wed Jul 28 2010 - 12:16:52 EST



On Jul 27, 2010, at 11:47 PM, Paul Mackerras wrote:

> On Tue, Jul 27, 2010 at 11:28:54AM -0500, Scott Wood wrote:
>
>> Doesn't the setting of .period need to be maintained (it is in the other
>> powerpc perf_event implementation that this is derived from)?
>
> Gah, yes it does.
>
>> I don't see how this is a security fix -- the existing initializer above
>> should zero-fill the fields that are not explicitly initialized. In fact,
>> it's taking other fields that were previously initialized to zero and is
>> making them uninitialized, since perf_sample_data_init only sets addr and
>> raw.
>
> So I misunderstood how an initializer for an automatic struct works.
> Brown paper bag time for me... :(
>
> Regarding the other fields, I assume Peter et al. have checked that
> they don't need to be cleared, so it's a microoptimization to not
> clear them.
>
>> CCing linuxppc-dev on the original patch would have been nice...
>
> True, but at least I can blame Peter Z. for that. :)
>
> Kumar and Ben, how do you want to proceed on this one?

If we aren't concerned about an oops being generated lets just submit a patch for 2.6.36.

- k
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