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

[Alexey Budankov]

On 07.08.2019 6:35, 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@xxxxxxxxxx>
> ---
>  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;

Makes sense to double check if it compiles with this change.

Regards,
Alexey

> -	bool privileged = geteuid() == 0 || perf_event_paranoid() < 0;
> +	bool privileged = perf_event_paranoid_check(-1);
>  	struct evsel *tracking_evsel;
>  	int err;
>  
> diff --git a/tools/perf/arch/x86/util/intel-bts.c b/tools/perf/arch/x86/util/intel-bts.c
> index 7b23318ebd7b..56a76142e9fd 100644
> --- a/tools/perf/arch/x86/util/intel-bts.c
> +++ b/tools/perf/arch/x86/util/intel-bts.c
> @@ -12,6 +12,7 @@
>  #include <linux/zalloc.h>
>  
>  #include "../../util/cpumap.h"
> +#include "../../util/event.h"
>  #include "../../util/evsel.h"
>  #include "../../util/evlist.h"
>  #include "../../util/session.h"
> @@ -107,7 +108,7 @@ static int intel_bts_recording_options(struct auxtrace_record *itr,
>  	struct perf_pmu *intel_bts_pmu = btsr->intel_bts_pmu;
>  	struct evsel *evsel, *intel_bts_evsel = NULL;
>  	const struct perf_cpu_map *cpus = evlist->core.cpus;
> -	bool privileged = geteuid() == 0 || perf_event_paranoid() < 0;
> +	bool privileged = perf_event_paranoid_check(-1);
>  
>  	btsr->evlist = evlist;
>  	btsr->snapshot_mode = opts->auxtrace_snapshot_mode;
> diff --git a/tools/perf/arch/x86/util/intel-pt.c b/tools/perf/arch/x86/util/intel-pt.c
> index 218a4e694618..43d5088ee824 100644
> --- a/tools/perf/arch/x86/util/intel-pt.c
> +++ b/tools/perf/arch/x86/util/intel-pt.c
> @@ -558,7 +558,7 @@ static int intel_pt_recording_options(struct auxtrace_record *itr,
>  	bool have_timing_info, need_immediate = false;
>  	struct evsel *evsel, *intel_pt_evsel = NULL;
>  	const struct perf_cpu_map *cpus = evlist->core.cpus;
> -	bool privileged = geteuid() == 0 || perf_event_paranoid() < 0;
> +	bool privileged = perf_event_paranoid_check(-1);
>  	u64 tsc_bit;
>  	int err;
>  
> diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
> index 64bc32ed6dfa..eafc134bf17c 100644
> --- a/tools/perf/util/evsel.c
> +++ b/tools/perf/util/evsel.c
> @@ -279,7 +279,7 @@ struct evsel *perf_evsel__new_idx(struct perf_event_attr *attr, int idx)
>  
>  static bool perf_event_can_profile_kernel(void)
>  {
> -	return geteuid() == 0 || perf_event_paranoid() == -1;
> +	return perf_event_paranoid_check(-1);
>  }
>  
>  struct evsel *perf_evsel__new_cycles(bool precise)
>