2009-11-08 16:08:12

by Pekka Enberg

Subject: [PATCH] perf tools: Fix permission checks

The perf_event_open() system call returns EACCES if the user is not root which
results in a very confusing error message:

$ perf record -A -a -f

Error: perfcounter syscall returned with -1 (Permission denied)

Fatal: No CONFIG_PERF_EVENTS=y kernel support configured?

It turns out that's because perf tools are checking only for EPERM. Fix that up
to get a much better error message:

$ perf record -A -a -f
Fatal: Permission error - are you root?

Cc: Peter Zijlstra <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Signed-off-by: Pekka Enberg <[email protected]>
---
tools/perf/builtin-record.c | 2 +-
tools/perf/builtin-top.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 3eeef33..a4be453 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -426,7 +426,7 @@ try_again:
if (fd[nr_cpu][counter] < 0) {
int err = errno;

- if (err == EPERM)
+ if (err == EPERM || err == EACCES)
die("Permission error - are you root?\n");
else if (err == ENODEV && profile_cpu != -1)
die("No such device - did you specify an out-of-range profile CPU?\n");
diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index a1b1d10..e23bc74 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -1027,7 +1027,7 @@ try_again:
if (fd[i][counter] < 0) {
int err = errno;

- if (err == EPERM)
+ if (err == EPERM || err == EACCES)
die("No permission - are you root?\n");
/*
* If it's cycles then fall back to hrtimer
--
1.6.3.3

2009-11-08 16:10:15

by Pekka Enberg

Subject: [tip:perf/urgent] perf tools: Fix permission checks

Commit-ID: c10edee2e1716f8cf217cf52ed01ae4742fcdf3c
Gitweb: http://git.kernel.org/tip/c10edee2e1716f8cf217cf52ed01ae4742fcdf3c
Author: Pekka Enberg <[email protected]>
AuthorDate: Sun, 8 Nov 2009 18:01:06 +0200
Committer: Ingo Molnar <[email protected]>
CommitDate: Sun, 8 Nov 2009 17:04:54 +0100

perf tools: Fix permission checks

The perf_event_open() system call returns EACCES if the user is
not root which results in a very confusing error message:

$ perf record -A -a -f

Error: perfcounter syscall returned with -1 (Permission denied)

Fatal: No CONFIG_PERF_EVENTS=y kernel support configured?

It turns out that's because perf tools are checking only for
EPERM. Fix that up to get a much better error message:

$ perf record -A -a -f
Fatal: Permission error - are you root?

Signed-off-by: Pekka Enberg <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
LKML-Reference: <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
---
tools/perf/builtin-record.c | 2 +-
tools/perf/builtin-top.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 3eeef33..a4be453 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -426,7 +426,7 @@ try_again:
if (fd[nr_cpu][counter] < 0) {
int err = errno;

- if (err == EPERM)
+ if (err == EPERM || err == EACCES)
die("Permission error - are you root?\n");
else if (err == ENODEV && profile_cpu != -1)
die("No such device - did you specify an out-of-range profile CPU?\n");
diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index a1b1d10..e23bc74 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -1027,7 +1027,7 @@ try_again:
if (fd[i][counter] < 0) {
int err = errno;

- if (err == EPERM)
+ if (err == EPERM || err == EACCES)
die("No permission - are you root?\n");
/*
* If it's cycles then fall back to hrtimer