Re: 2.25 freeze status

[Carlos O'Donell <carlos at redhat dot com>]

On 01/30/2017 05:48 AM, Florian Weimer wrote:
> On 01/30/2017 11:25 AM, Phil Blundell wrote:
>> On Sat, 2017-01-28 at 19:00 -0500, Carlos O'Donell wrote:
>>>
>>> Whatever we might think about the seriousness of the issue, it has
>>> existed
>>> for 4 or 5 releases and few people have run into it, which means we
>>> have
>>> time to fix it i.e. not a blocker.
>>
>> That's not an entirely accurate characterisation.  Bug 20019 has indeed
>> existed for several releases without anybody noticing, but bug 21041 is
>> new.
> 
> Phil, thanks for spelling this out explicitly.
> 
>> The effect of the older bug 20019 is that affected programs would be at
>> risk of crashing if they called longjmp().  But the effect of the newer
>> bug 21041 is that such programs cannot start up at all, even if they
>> never in fact call longjmp() at runtime.
> 
> I share this concern.

This is enough concern that I now propose we back out the fix for 20019
until we can find an acceptable fix in glibc 2.26.

H.J.,

Could you please back out the fix for bug 20019?

We will continue to try and fix this in 2.26 with a solution that moves
IFUNC design towards a better documented set of semantics.

commit 0e6d3adc60d8073397af6a320e594d98d7fbedde
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Fri Oct 28 09:11:55 2016 -0700

    Check IFUNC definition in unrelocated shared library [BZ #20019]
    
    Calling an IFUNC function defined in unrelocated shared library may
    lead to segfault.  This patch issues an error message to request
    relinking the shared library if it references IFUNC function defined
    in the unrelocated shared library.
    
            [BZ #20019]
            * sysdeps/i386/dl-machine.h (elf_machine_rel): Check IFUNC
            definition in unrelocated shared library.
            * sysdeps/x86_64/dl-machine.h (elf_machine_rela): Likewise.

-- 
Cheers,
Carlos.