From: Arnaldo Carvalho de Melo <acme@kernel.org>
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, James Morris <jmorris@namei.org>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Ingo Molnar <mingo@redhat.com>,
Namhyung Kim <namhyung@kernel.org>, Jiri Olsa <jolsa@redhat.com>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v3 4/4] perf: Use CAP_SYS_ADMIN instead of euid==0 with ftrace
Date: Mon, 12 Aug 2019 17:27:06 -0300 [thread overview]
Message-ID: <20190812202706.GH9280@kernel.org> (raw)
In-Reply-To: <20190812202251.GG9280@kernel.org>
Em Mon, Aug 12, 2019 at 05:22:51PM -0300, Arnaldo Carvalho de Melo escreveu:
> Em Wed, Aug 07, 2019 at 10:44:17AM -0400, Igor Lubashev escreveu:
> > Kernel requires CAP_SYS_ADMIN instead of euid==0 to mount debugfs for ftrace.
> > Make perf do the same.
> >
> > Signed-off-by: Igor Lubashev <ilubashe@akamai.com>
> > ---
> > tools/perf/builtin-ftrace.c | 4 +++-
> > 1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c
> > index ae1466aa3b26..d09eac8a6d57 100644
> > --- a/tools/perf/builtin-ftrace.c
> > +++ b/tools/perf/builtin-ftrace.c
> > @@ -13,6 +13,7 @@
> > #include <signal.h>
> > #include <fcntl.h>
> > #include <poll.h>
> > +#include <linux/capability.h>
> >
> > #include "debug.h"
> > #include <subcmd/parse-options.h>
> > @@ -21,6 +22,7 @@
> > #include "target.h"
> > #include "cpumap.h"
> > #include "thread_map.h"
> > +#include "util/cap.h"
> > #include "util/config.h"
> >
> >
> > @@ -281,7 +283,7 @@ static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)
> > .events = POLLIN,
> > };
> >
> > - if (geteuid() != 0) {
> > + if (!perf_cap__capable(CAP_SYS_ADMIN)) {
> > pr_err("ftrace only works for root!\n");
>
> I guess we should update the error message too?
>
I.e. I applied this as a follow up patch:
diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c
index 01a5bb58eb04..ba8b65c2f9dc 100644
--- a/tools/perf/builtin-ftrace.c
+++ b/tools/perf/builtin-ftrace.c
@@ -284,7 +284,12 @@ static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)
};
if (!perf_cap__capable(CAP_SYS_ADMIN)) {
- pr_err("ftrace only works for root!\n");
+ pr_err("ftrace only works for %s!\n",
+#ifdef HAVE_LIBCAP_SUPPORT
+ "users with the SYS_ADMIN capability"
+#else
+ "root"
+#endif
return -1;
}
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next prev parent reply other threads:[~2019-08-12 20:27 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-07 14:44 [PATCH v3 0/4] perf: Use capabilities instead of uid and euid Igor Lubashev
2019-08-07 14:44 ` [PATCH v3 1/4] perf: Add capability-related utilities Igor Lubashev
2019-08-12 19:43 ` Arnaldo Carvalho de Melo
2019-08-07 14:44 ` [PATCH v3 2/4] perf: Use CAP_SYS_ADMIN with perf_event_paranoid checks Igor Lubashev
2019-08-12 20:01 ` Arnaldo Carvalho de Melo
2019-08-12 20:15 ` Arnaldo Carvalho de Melo
2019-08-12 22:33 ` Lubashev, Igor
2019-08-13 13:20 ` Arnaldo Carvalho de Melo
2019-08-07 14:44 ` [PATCH v3 3/4] perf: Use CAP_SYSLOG with kptr_restrict checks Igor Lubashev
2019-08-14 18:04 ` Mathieu Poirier
2019-08-14 18:48 ` Arnaldo Carvalho de Melo
2019-08-14 18:52 ` Arnaldo Carvalho de Melo
2019-08-14 20:02 ` Lubashev, Igor
2019-08-15 15:01 ` Mathieu Poirier
2019-08-15 20:16 ` Mathieu Poirier
2019-08-15 21:42 ` Arnaldo Carvalho de Melo
2019-08-19 16:51 ` Mathieu Poirier
2019-08-19 22:22 ` Lubashev, Igor
2019-08-20 16:57 ` Mathieu Poirier
2019-08-20 17:13 ` Arnaldo Carvalho de Melo
2019-08-27 1:58 ` Lubashev, Igor
2019-08-15 22:27 ` Lubashev, Igor
2019-08-07 14:44 ` [PATCH v3 4/4] perf: Use CAP_SYS_ADMIN instead of euid==0 with ftrace Igor Lubashev
2019-08-12 20:22 ` Arnaldo Carvalho de Melo
2019-08-12 20:27 ` Arnaldo Carvalho de Melo [this message]
2019-08-12 20:29 ` Arnaldo Carvalho de Melo
2019-08-12 21:42 ` Mathieu Poirier
2019-08-13 13:23 ` Arnaldo Carvalho de Melo
2019-08-13 16:35 ` Mathieu Poirier
2019-08-12 9:13 ` [PATCH v3 0/4] perf: Use capabilities instead of uid and euid Jiri Olsa
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