[PATCH 2/2] linux: Make profil_counter a compat_symbol (BZ#17726)

Florian Weimer fw@deneb.enyo.de
Tue Aug 6 19:18:00 GMT 2019


* Carlos O'Donell:

> On 8/5/19 3:41 PM, Florian Weimer wrote:
>> * Joseph Myers:
>> 
>>> On Mon, 5 Aug 2019, Adhemerval Zanella wrote:
>>>
>>>> Also that this symbol export was not meant in first place, so it is unlikely
>>>
>>> Like all other exports, it's listed in a Versions file.  So it must have
>>> been deliberate (even if mistaken) at some point.
>> 
>> libc.map used to have this:
>> 
>>      # all functions and variables in the normal name space
>>      a*; b*; c*; d*; e*; f*; g*; h*; i*; j*; k*; l*; m*;
>>      n*; o*; p*; q*; r*; s*; t*; u*; v*; w*; x*; y*; z*;
>> 
>> So the missing static likely triggered the unwanted export, and that
>> mistake was carried over when libc.map was switched over to explicit
>> function names.  I do not see evidence of a deliberate decision here.
>   
> This is why we say "strong presumption" :-)
>
> We want to err on the side of being cautious unless we have evidence
> otherwise.
>
> If there is no evidence that a deliberate and conscious decision was
> made, then perhaps simplifying the situation may be fine e.g. no compat
> symbols.

And if necessary, we can add back the symbol again.  As far as
mistakes go, it wouldn't even be that costly, I think.



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