From: Peter Zijlstra <peterz@infradead.org>
To: Stephane Eranian <eranian@google.com>
Cc: yao.jin@linux.intel.com,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Jiri Olsa <jolsa@kernel.org>, Ingo Molnar <mingo@redhat.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
me@kylehuey.com, LKML <Linux-kernel@vger.kernel.org>,
Vince Weaver <vincent.weaver@maine.edu>,
Will Deacon <will.deacon@arm.com>,
Namhyung Kim <namhyung@kernel.org>,
Andi Kleen <ak@linux.intel.com>,
"Liang, Kan" <kan.liang@intel.com>,
"Jin, Yao" <yao.jin@intel.com>
Subject: Re: [PATCH v1 1/2] perf/core: Use sysctl to turn on/off dropping leaked kernel samples
Date: Fri, 15 Jun 2018 10:16:56 +0200 [thread overview]
Message-ID: <20180615081656.GC2458@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <CABPqkBTyEZX7DebLR-nbzXs0ZYGT1xWNmOmvKgRsvr4mxWJg=w@mail.gmail.com>
On Thu, Jun 14, 2018 at 11:02:53PM -0700, Stephane Eranian wrote:
> On Thu, Jun 14, 2018 at 7:10 PM Jin Yao <yao.jin@linux.intel.com> wrote:
> > + /*
> > + * Due to interrupt latency (AKA "skid"), we may enter the
> > + * kernel before taking an overflow, even if the PMU is only
> > + * counting user events.
> > + * To avoid leaking information to userspace, we must always
> > + * reject kernel samples when exclude_kernel is set.
> > + */
> > + if (event->attr.exclude_kernel && !user_mode(regs))
> > + return false;
> > +
> And how does that filter PEBS or LBR records?
I suspect the user_mode() thing actually covers PEBS, but yes LBR might
need additional filtering.
next prev parent reply other threads:[~2018-06-15 8:17 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-15 10:03 [PATCH v1 0/2] perf: Drop leaked kernel samples Jin Yao
2018-06-15 3:35 ` Kyle Huey
2018-06-15 5:11 ` Jin, Yao
2018-06-15 17:16 ` Kyle Huey
2018-06-15 17:34 ` Robert O'Callahan
2018-06-16 0:50 ` Jin, Yao
2018-06-16 0:56 ` Kyle Huey
2018-06-16 1:18 ` Jin, Yao
2018-06-15 7:45 ` Peter Zijlstra
2018-06-15 8:01 ` Jin, Yao
2018-06-15 8:12 ` Peter Zijlstra
2018-06-15 8:24 ` Jin, Yao
2018-06-15 16:54 ` Stephane Eranian
2018-06-15 10:03 ` [PATCH v1 1/2] perf/core: Use sysctl to turn on/off dropping " Jin Yao
2018-06-15 5:59 ` Stephane Eranian
2018-06-15 7:15 ` Jin, Yao
2018-06-19 16:50 ` Stephane Eranian
2018-06-15 6:02 ` Stephane Eranian
2018-06-15 8:16 ` Peter Zijlstra [this message]
2018-06-15 13:31 ` Liang, Kan
2018-06-18 10:41 ` Peter Zijlstra
2018-06-15 11:36 ` Mark Rutland
2018-06-16 1:27 ` Linus Torvalds
2018-06-18 10:51 ` Peter Zijlstra
2018-06-18 6:55 ` Jin, Yao
2018-06-18 10:45 ` Peter Zijlstra
2018-06-19 1:39 ` Jin, Yao
2018-06-19 6:01 ` Mark Rutland
2018-06-15 10:03 ` [PATCH v1 2/2] perf Documentation: Introduce the sysctl perf_allow_sample_leakage Jin Yao
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