[Users] gcc Version

[Kir Kolyshkin]

On 05/19/2015 04:56 PM, Gena Makhomed wrote:
> On 19.05.2015 2:31, Kir Kolyshkin wrote:
>
>>>> could you please explain the problem in more details?
>
>>>>> is there a special reason why you use a different gcc Version for the
>>>>> kernels you provide
>>>>> cat /proc/version
>>>>> Linux version 2.6.32-042stab106.4 (root at kbuild-rh6-x64) (gcc version
>>>>> 4.4.6 20120305 (Red Hat 4.4.6-4) (GCC) ) #1 SMP Fri Mar 27 15:19:28
>>>>> MSK 2015
>>>>> that either CentOS6 or RHEL6 ship with:
>>>>> gcc -v
>>>>> gcc-Version 4.4.7 20120313 (Red Hat 4.4.7-11) (GCC)
>>>
>>> problem is difference between gcc 4.4.6 20120305 and gcc 4.4.7-11
>>
>> Can you please be more specific of what the exact problem is
>> (unfortunately I forgot my crystal ball at home today)?
>
> gcc 4.4.6-4 contains many bugs, which already fixed in 4.4.7-11
>
> and these gcc bugs can originate bugs in OpenVZ kernel,
> compiled with this very old and buggy gcc version.

Theoretically, you are right -- updated gcc version should be better, 
less buggy etc.

Practically, we are not aware of any single issue with gcc 4.4.6 and 
RHEL6-based
kernel -- neither in our kernel, nor in upstream (i.e. RHEL6). We saw 
some bugs
in the past that were caused by gcc miscompiling the kernel source code, 
but it
was always a version of gcc not from RHEL.

>
> more specific:
>
> https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.4.7 
>
>
> - list of problem reports (PRs) from GCC's bug tracking system that 
> are known to be fixed in the 4.4.7 release. This list might not be 
> complete (that is, it is possible that some PRs that have been fixed 
> are not listed here)
>
> also see output of # rpm -q --changelog gcc | less
> to see Red Hat backports and fixes over gcc version 4.4.7

If you could point out to any fixes made specifically to fix 
kernel-related problems,
we'd be very grateful. Otherwise, this becomes "would be nice to use 
updated gcc"
rather than "it's a must to use updated gcc" sort of thing.

Having said that, we'll probably update our build environments anyway.

Kir.