Re: [uml-devel] [PATCH 06/10] uml: run mconsole "sysrq" in process context
From: Blaisorblade
Date: Thu Sep 22 2005 - 15:56:36 EST
On Thursday 22 September 2005 22:37, Jeff Dike wrote:
> On Thu, Sep 22, 2005 at 09:20:20PM +0200, Blaisorblade wrote:
> > sysrq t is broken (and stays),
> There's a fix on the way for that.
Already found? Nice.
> This has nothing to do with interrupt
> context anyway.
> > but additionally there are some warnings from
> > some commands (enable sleep inside spinlock checking and spinlock
> > debugging), which go to the down_read inside handle_page_fault IIRC. So
> > try to run in process context.
> Which ones? They should be fixed.
Ok, will drop this patch and retry again to look at the messages.
> It is fairly fundamental to sysrq that it work from interrupt context. You
> may be diagnosing a system which can't context switch any more.
Ok, I felt a bit uncertain about this, but didn't realize this very problem.
> This patch should be dropped, and the real problems fixed.
Ok, that's nice for me. I'll look into this. Possibly, the
if (in_atomic()) don't take semaphore in handle_page_fault was the right fix
for this. I'll have a look soon.
> Jeff
--
Inform me of my mistakes, so I can keep imitating Homer Simpson's "Doh!".
Paolo Giarrusso, aka Blaisorblade (Skype ID "PaoloGiarrusso", ICQ 215621894)
http://www.user-mode-linux.org/~blaisorblade
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