[PATCH][BZ #13724] Do not segfault in pthread_setname_np (x, NULL)

[Carlos O'Donell]

On 10/07/2013 06:40 PM, Roland McGrath wrote:
>> I agree with Jeff Law on this one, this is not a performance
>> critical routine and checking arguments and returning EFAULT
>> is good for QoI.
> 
> Historically we've considered it a QoI feature not to mask user bugs in
> this way.  If passing a bad pointer has undefined behavior, it is far more
> useful in the long run if it crashes quickly rather than diagnosing an
> error that is probably ignored by the flaky caller.

Roland, Rich,
 
Two against one here, and I trust your judgement and Rich's judgement,
having seen much more crappy code than I will ever imagine.

I've added a section to our "Style and Conventions" guide about invalid pointers:
https://sourceware.org/glibc/wiki/Style_and_Conventions#Invalid_pointers

Please review.

Ondrej,

Would you still be interested in adding a small entry to the manual to
say that NULL pointers are not accepted, and that if you want to remove
the program name for the thread to call pthread_setname_np (th, "");
instead of pthread_setname_np (th, NULL); which would just have failed
with -EFAULT when the kernel prctrl call was made.

Is everyone in agreement here?

Cheers,
Carlos.