Re: [PATCH] perf: powerpc: Disable pagefaults during callchainstack read

From: Benjamin Herrenschmidt
Date: Mon Aug 01 2011 - 06:40:06 EST


On Mon, 2011-08-01 at 11:59 +0200, Peter Zijlstra wrote:
> > Signed-off-by: David Ahern <dsahern@xxxxxxxxx>
> > CC: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
> > CC: Anton Blanchard <anton@xxxxxxxxx>
>
> Hmm, Paul, didn't you fix something like this early on? Anyway, I've
> no
> objections since I'm really not familiar enough with the PPC side of
> things.

I'm travelling so I haven't had a chance to review properly or even test
but it looks like an ad-hoc fix for the immediate problem.

Ultimately, I want to rework that stuff to do a __gup_fast like x86 does
(maybe as a fallback from an attempt at access first) so we work around
access permissions blocked by lack of dirty/accessed bits but in the
meantime, this should fix the immediate issue.

Cheers,
Ben.


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/