linux-kernel - Re: [PATCH v1 0/2] perf: Drop leaked kernel samples

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Message-ID: <20180615074504.GA2458@hirez.programming.kicks-ass.net>
Date:   Fri, 15 Jun 2018 09:45:04 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Jin Yao <yao.jin@...ux.intel.com>
Cc:     acme@...nel.org, jolsa@...nel.org, mingo@...hat.com,
        alexander.shishkin@...ux.intel.com, me@...ehuey.com,
        Linux-kernel@...r.kernel.org, vincent.weaver@...ne.edu,
        will.deacon@....com, eranian@...gle.com, namhyung@...nel.org,
        ak@...ux.intel.com, kan.liang@...el.com, yao.jin@...el.com
Subject: Re: [PATCH v1 0/2] perf: Drop leaked kernel samples

On Fri, Jun 15, 2018 at 06:03:21PM +0800, Jin Yao wrote:
> On workloads that do a lot of kernel entry/exits we see kernel
> samples, even though :u is specified. This is due to skid existing.
> 
> This might be a security issue because it can leak kernel addresses even
> though kernel sampling support is disabled.
> 
> One patch "perf/core: Drop kernel samples even though :u is specified"
> was posted in last year but it was reverted because it introduced a
> regression issue that broke the rr-project.
> 
> Now this patch set uses sysctl to control the dropping of leaked
> kernel samples.

So what happened to the suggestion of keeping the samples but 0-stuffing
all the tricky bits?