Preventing preemption of 'protected' symbols in GNU ld 2.26 [aka should we revert the fix for 65248]

[Alan Modra]

On Mon, Apr 18, 2016 at 11:01:48AM +0200, Richard Biener wrote:
> To summarize: there is currently no testcase for a wrong-code issue
> because there is no wrong-code issue.

That depends entirely on how far you are willing to bend the ELF gABI.

Any testcase the takes the address of a protected visibility variable
defined in a shared library now can get the wrong answer, since you
can argue that any address outside the shared library is wrong
according to the gABI.

I expect you can also write a testcase using a const protected var in
a shared library that ought to segfault on writing to the var from
code within the shared library, that now merrily writes to a .dynbss
copy.

-- 
Alan Modra
Australia Development Lab, IBM