Date: Sat, 5 Nov 2005 15:33:04 -0800
From: Andrew Morton <akpm@osdl.org>
To: Ashok Raj <ashok.raj@intel.com>
Cc: ashok.raj@intel.com, rjw@sisk.pl, linux-kernel@vger.kernel.org,
       davej@codemonkey.org.uk, mingo@elte.hu, linux@brodo.de,
       venkatesh.pallipadi@intel.com
Subject: Re: 2.6.14-git3: scheduling while atomic from cpufreq on Athlon64
Message-Id: <20051105153304.09a1a4dc.akpm@osdl.org>
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Ashok Raj <ashok.raj@intel.com> 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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