Re: Python stops working after upgrade

2013.Május 29.(Sze) 03:29 időpontban Anthony G. Basile ezt írta:
> On 05/28/2013 07:46 PM, "Tóth Attila" wrote:
>> If PT_PAX has E, python2.7 would not start on my system.
>> Let's correct that:
>> paxctl-ng -e /usr/bin/python2.7
>>
>> Now python works again.
>
> Something changed in the latest python upgrades because I'm having
> problems of a different nature.  I'll have to investigate.
>

I wanted the community to know, that the situation looks scary for the
first time, but there's an easy fix. In case anybody else runs into this.

>>
>> Sidenote:
>> Even after running migrate-pax -m, there are binaries on the system
>> having
>> only PT_PAX marking. Example:
>> migrate-pax -m
>> paxctl-ng -v /usr/bin/clear
>> /usr/bin/clear:
>>          PT_PAX    : -e---
>>          XATTR_PAX : not found
>>
>
> Unfortunately it is very difficult to find everything that links against
> everything on a system.  First there's just a simple logistic problem,
> going through all ELF on a system and running ldd (or readelf -d) is
> time consuming and likely to miss stuff.  On gentoo with portage (not
> paludis!) we have linkage info in NEEDED.ELF.2 in vdb created at build
> time by examing linkage info, but this also can't be everything.
> Consider plugins that dlopen-ed at runtime.
>
> So something will be missed.

Is there an easy command I can use to list binaries having PT_PAX flags
and missing XATTR_PAX flags?

>
> BUT!
>
> That's not what's happening there.  No XATTR_PAX flags implies the
> default markings which is "-e---".  This is so we don't have to go
> around creating xattrs on every ELF binary on your system just to get
> the default.  Upstream wanted it that way and it does make sense.

According to my recent experience, if EMUTRAMP is enabled by a PT_PAX flag
and there's no XATTR_PAX flag present, the system will listen to the
PT_PAX flag. Can I influence this behavior to rather use the mentioned
XATTR_PAX default and don't pay attention to the PT_PAX flag?

Thanks:
Dw.

-- 
dr Tóth Attila, Radiológus, 06-20-825-8057
Attila Toth MD, Radiologist, +36-20-825-8057