From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Ahern <david.ahern@oracle.com>
Date: Tue, 31 Mar 2015 23:52:53 +0000
Subject: Re: sparc: deadlock using perf with sched tracepoints and user callstacks
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List-Id: <sparclinux.vger.kernel.org>
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To: sparclinux@vger.kernel.org

On 3/31/15 5:38 PM, David Miller wrote:
> What is different in the PowerPC fault path vs. the Sparc one that
> causes the SIGBUS for sparc where the PowerPC does not see it?
>
> I don't understand where the SIGBUS comes from.  In a pagefault
> disable section on sparc, in_atomic() should be true, thus we'll call
> do_kernel_fault(), fall through to the TSTATE_PRIV code path and
> simply run the exception handler.
>

That's what I was hoping someone could explain to me. I'll dig deeper on 
Monday.