Re: [PATCH v2 2/4] perf: Use CAP_SYS_ADMIN with perf_event_paranoid checks

From: Jiri Olsa <jolsa@redhat.com>
To: Igor Lubashev <ilubashe@akamai.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Alexey Budankov <alexey.budankov@linux.intel.com>,
	linux-kernel@vger.kernel.org,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	James Morris <jmorris@namei.org>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Ingo Molnar <mingo@redhat.com>,
	Namhyung Kim <namhyung@kernel.org>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 2/4] perf: Use CAP_SYS_ADMIN with perf_event_paranoid checks
Date: Wed, 7 Aug 2019 13:46:02 +0200	[thread overview]
Message-ID: <20190807114602.GB9605@krava> (raw)
In-Reply-To: <70ce92d9c252bbafa883a6b5b3c96cf10d1a5b31.1565146171.git.ilubashe@akamai.com>

On Tue, Aug 06, 2019 at 11:35:55PM -0400, Igor Lubashev wrote:
> The kernel is using CAP_SYS_ADMIN instead of euid==0 to override
> perf_event_paranoid check. Make perf do the same.
> 
> Signed-off-by: Igor Lubashev <ilubashe@akamai.com>
> ---
>  tools/perf/arch/arm/util/cs-etm.c    | 3 ++-
>  tools/perf/arch/arm64/util/arm-spe.c | 4 ++--
>  tools/perf/arch/x86/util/intel-bts.c | 3 ++-
>  tools/perf/arch/x86/util/intel-pt.c  | 2 +-
>  tools/perf/util/evsel.c              | 2 +-
>  5 files changed, 8 insertions(+), 6 deletions(-)
> 
> diff --git a/tools/perf/arch/arm/util/cs-etm.c b/tools/perf/arch/arm/util/cs-etm.c
> index 5cb07e8cb296..b87a1ca2968f 100644
> --- a/tools/perf/arch/arm/util/cs-etm.c
> +++ b/tools/perf/arch/arm/util/cs-etm.c
> @@ -18,6 +18,7 @@
>  #include "../../perf.h"
>  #include "../../util/auxtrace.h"
>  #include "../../util/cpumap.h"
> +#include "../../util/event.h"
>  #include "../../util/evlist.h"
>  #include "../../util/evsel.h"
>  #include "../../util/pmu.h"
> @@ -254,7 +255,7 @@ static int cs_etm_recording_options(struct auxtrace_record *itr,
>  	struct perf_pmu *cs_etm_pmu = ptr->cs_etm_pmu;
>  	struct evsel *evsel, *cs_etm_evsel = NULL;
>  	struct perf_cpu_map *cpus = evlist->core.cpus;
> -	bool privileged = (geteuid() == 0 || perf_event_paranoid() < 0);
> +	bool privileged = perf_event_paranoid_check(-1);
>  	int err = 0;
>  
>  	ptr->evlist = evlist;
> diff --git a/tools/perf/arch/arm64/util/arm-spe.c b/tools/perf/arch/arm64/util/arm-spe.c
> index 00915b8fd05b..200bc973371b 100644
> --- a/tools/perf/arch/arm64/util/arm-spe.c
> +++ b/tools/perf/arch/arm64/util/arm-spe.c
> @@ -12,6 +12,7 @@
>  #include <time.h>
>  
>  #include "../../util/cpumap.h"
> +#include "../../util/event.h"
>  #include "../../util/evsel.h"
>  #include "../../util/evlist.h"
>  #include "../../util/session.h"
> @@ -65,8 +66,7 @@ static int arm_spe_recording_options(struct auxtrace_record *itr,
>  	struct arm_spe_recording *sper =
>  			container_of(itr, struct arm_spe_recording, itr);
>  	struct perf_pmu *arm_spe_pmu = sper->arm_spe_pmu;
> -	struct evsel *evsel, *arm_spe_evsel = NULL;

wouldn't this removal break the compilation on arm?

jirka

> -	bool privileged = geteuid() == 0 || perf_event_paranoid() < 0;
> +	bool privileged = perf_event_paranoid_check(-1);
>  	struct evsel *tracking_evsel;
>  	int err;

SNIP

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