On 05/28/2015 06:56 PM, Fernando Lopez-Lezcano wrote:
> Oh well. Second time the machine hangs in two days in the same way
> (otherwise very stable running 3.18.x-rty)
>
> (this is a bumblebee + bbswitch graphics laptop - argh, if I had known
> better...)
>
> ----
> May 28 18:49:21 localhost kernel: ------------[ cut here ]------------
> May 28 18:49:21 localhost kernel: kernel BUG at mm/memcontrol.c:5848!
> May 28 18:49:21 localhost kernel: invalid opcode: 0000 [#1] PREEMPT SMP
...
> ----

This is still happening, about once a day. John Dulaney help me set up a 
crash kernel dump (thanks!) so now I have a kernel core dump for this 
one, I'll try to post more details tomorrow. Let me know if there is 
anything in particular I should look at.

I'm attaching another backtrace on a different machine (older desktop), 
slightly different but same end result.

-- Fernando