Re: [gentoo-user] System borked after emerge -e world

[Dale]

wabe wrote:
> Dale <rdalek1967@×××××.com> wrote:
>
>> wabe wrote:
>>> Hi folks,
>>>
>>> it seems that my system is broken after recompiling everything with
>>> the new gcc5.
>>>
>>> I even cannot execute any command or start new programs. It is also
>>> not possible to open a terminal or to login on console.
>>>
>>> When I type something in an already opened Xterm it says
>>> "Ungültiger Maschinenbefehl" (in English probably something like
>>> "invalid machine command").
>>>
>>> On tty12 I can see messages like this:
>>>
>>> traps: ls[4055] trap invalid opcode ip:3cd3d91e024 sp:3d6a804abb0
>>> error:0 in libc-2.23.so[3cd3d865000+19d000] grsec: Illegal
>>> instruction occured at 000003cd3d91e026 in /bin/ls[ls:4055]
>>> uid/euid:0/0 gid/egid:0/0, parent...
>>>
>>> kernel is 4.8.17-hardened-r2
>>>
>>> (uname -a is still working).
>>>
>>> I don't dare to reboot my system because I'm not sure that it will
>>> boot.
>>>
>>> I don't even know if this email will reach the list, because claws
>>> mail also dropped some errors about "bogofilter doesn't work".
>>>
>>> Any help would really appreciated.
>>>
>>> --
>>> Regards
>>> wabe
>>>
>>> .
>>>
>> I wonder if this is related.  When I did my switch, I hit a point
>> where I had to start the alt sysreq key sequence.  I only had to do
>> the R and E part to get my console back tho.  At the time, I thought
>> it may just be some weird occurrence but now I wonder if it was
>> related to some update.  Once I got my console and login screen, I
>> was able to login and carry on, after getting all the services back
>> running that got killed off.  I got the login screen back after
>> hitting the E part.
>>
>> I wonder, will others run into this sort of problem?  If so, what is
>> the best way to get back to normal?  For you, rebooting helped.  For
>> me, just starting the alt sysreq did the trick.  It makes one wonder.
> Hi Dale,
>
> thanks for this hint. Although I know about this "magic stuff", I don't
> even have it enabled in my kernel. At the moment I'm happy that my
> system is working again so that I can do some other urgent tasks. But
> I will look closely at these function within the next time. Even when
> it is not possible to "repair" the system in the case of a crash, it is
> helpful to be able to write the cache to disk and reboot the system.
>
> --
> Regards
> wabe
>
>


It's rare that I have to go "all the way" with this but at least it does
flush things through the system and properly unmounts file systems
first.  That alone is some comfort.  I switched to ext4 which is
supposed to handle those things pretty well BUT why risk it if you can
unmount them properly, even if it is brute force. 

One thing about alt sysreq, once you get to a certain point, you have to
go "all the way" with it.  I've found that just the R and E generally
gets things back to a point it is accessible and I don't have to go
through it all.  I think once you get to the I or S, it's all or nothing
at that point.  Even after the E, you may have to start/restart some
init processes.  FYI, I'm pretty sure the S is what syncs the file
systems and the U unmounts everything.  Of course, the B reboots.  I
can't recall what the others do exactly.

I wonder if some guru that is familiar with this could shine some light
and share some wisdom. 

Dale

:-)  :-)