Re: [PATCH] perf,x86: fix uninitialized pt_regs inintel_pmu_drain_bts_buffer()

From: Peter Zijlstra
Date: Tue Mar 19 2013 - 08:58:49 EST

On Tue, 2013-03-19 at 13:50 +0100, Stephane Eranian wrote:
> > Should we not replace:
> >
> > regs.ip = 0;
> >
> > with that memset? It avoids the memset work in a few cases and
> removes
> > the then superfluous clearing of the IP field.
> >
> We could drop it because it's covered by the memset().

Yeah, but also place the memset a little lower than you did, avoids the
stack writes when not needed.

> The issue here was that you eventually end up in code_segment_base()
> which
> looks at other uninitialized fields in pt_regs and may cause breakage.

Right, your changelog said so ;-)

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