Re: How to debug X lockup (advice from gurus wanted)
On 08/30/2011 09:24 PM, stan wrote:
On Mon, 29 Aug 2011 21:06:29 +0200
Roberto Ragusa <mail(a)robertoragusa.it> wrote:
> Hi,
>
> it sometimes happens to me that X completely locks up, while the
> machine is still alive on the network.
>
> This is on F14, untainted kernel, nouveau driver, no 3D used,
> KDE desktop on a 32-bit machine with 8GiB RAM and PAE kernel.
> It typically happens when something is going to be drawn on
> the screen (a window pops up or virtual desktop change).
>
> I would like to open a bug, but I'm not able to attach any kind
> of usable log; dmesg says nothing, all I can say is that
> the screen remains frozen (including the pointer), the X
> server and the kernel keep doing some "SIG ALRM" stuff and
> any attempt to access the X server stalls the command (xrandr
> or xset, for example), in a Ctrl-C responsive way.
>
> Any idea?
>
I had this problem in F14 while using the stock kernel. When I
compiled a custom kernel it went away. While I made *many* changes, I
think the one that mattered was turning off SMP on my single core
system. I suspect, without proof, that the SMP code was occasionally
causing a race condition, and a deadlock. Other possible causes for
fix: moved to pre-emptable desktop, reserved 128 K low memory for
kernel, moved to deadline scheduler.
You could open a bug against the kernel, but it has moved on so far
that it will probably languish.
[now crossposting fedora, fedora-devel]
Hmmm, turning off SMP is not realistic, as this laptop has a Core 2 Duo.
I had been compiling my kernels until many years ago, and I would like
to stay with the distro's kernel.
I hope that upgrading to F15/F16 will mix things up and solve this in some
way.
Opening a bug seems a waste of time.
I'm cross-posting to fedora-devel, in case someone can suggest how to
collect useful info to open a kernel bug.
Thanks.
--
Roberto Ragusa mail at robertoragusa.it