Re: [PATCH] perf/core: generate overflow signal when samples are dropped (WAS: Re: [REGRESSION] perf/core: PMU interrupts dropped if we entered the kernel in the "skid" region)
From: Mark Rutland
Date: Tue Jul 04 2017 - 06:23:05 EST
On Tue, Jul 04, 2017 at 10:33:45AM +0100, Mark Rutland wrote:
> On Tue, Jul 04, 2017 at 11:03:13AM +0200, Peter Zijlstra wrote:
> > Faking data gets a wee bit tricky in how much data we need to clear
> > through, its not only IP, pretty much everything we get from the
> > interrupt context, like the branch stack and registers is also suspect.
> Indeed. I'll take a run through __perf_event_output() and callees, and
> see what we need to drop.
Looking at perf_event_sample_format in uapi/linux/perf_event.h, there
are samples that are obviously sensitive, and should be dropped:
... samples that look benign:
.. and samples that I have no idea about:
Should any of those be moved into the "should be dropped" pile?