[RESEND PATCH v9] Mutex: Add pthread mutex tunables

[kemi]

On 2018/11/29 下午10:41, Florian Weimer wrote:
> * Kemi Wang:
> 
>> +# 	     SXID_ERASE: (default) Don't read for AT_SECURE binaries and
>> +# 	     		 removed so that child processes can't read it.
> 
> I think this will not work as intended for libpthread tunables because
> if libpthread is not linked in, no code in nptl/nptl-init.c ever runs.
> 

this tunable is for pthread mutex. If the libpthread is not linked in,
it seems reasonable that we can't use this tunables.

Why do we need to move to elf/dl-tunables.list and do some tricks?

> I think we need to move the tunable to elf/dl-tunables.list, parse it
> there, and communicate the result to libpthread, possibly via
> _rtld_global_ro.
> 
> Thanks,
> Florian
>