Re: 2.6.14-git3: scheduling while atomic from cpufreq on Athlon64

From: Andrew Morton
Date: Sat Nov 05 2005 - 18:33:17 EST


Ashok Raj <ashok.raj@xxxxxxxxx> wrote:
>
> Now we leave a trace in current->flags indicating current thread already
> is under cpucontrol lock held, so we dont attempt to do this another time.
>
> ..
> +#define PF_HOTPLUG_CPU 0x01000000 /* Currently performing CPU hotplug */
>

It's still hacky - I mean, we could use this trick to avoid recursion onto
any lock in the kernel whenever we get ourselves into a mess. We'd gain an
awful lot of PF_* flags.

So we should still view this as a temporary fix.

I don't think I've seen an analysis of the actual deadlock yet. Are you
able to provide a stack trace of the offending callpath?
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