[PATCH] perf tools: Fix permission checks

[Pekka Enberg]

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 <a.p.zi...@chello.nl>
Cc: Paul Mackerras <pau...@samba.org>
Cc: Frederic Weisbecker <fwei...@gmail.com>
Signed-off-by: Pekka Enberg <pen...@cs.helsinki.fi>
---
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

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majo...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

[tip-bot for Pekka Enberg]

Commit-ID: c10edee2e1716f8cf217cf52ed01ae4742fcdf3c
Gitweb: http://git.kernel.org/tip/c10edee2e1716f8cf217cf52ed01ae4742fcdf3c
Author: Pekka Enberg <pen...@cs.helsinki.fi>
AuthorDate: Sun, 8 Nov 2009 18:01:06 +0200
Committer: Ingo Molnar <mi...@elte.hu>
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 <pen...@cs.helsinki.fi>

Cc: Peter Zijlstra <a.p.zi...@chello.nl>
Cc: Paul Mackerras <pau...@samba.org>
Cc: Frederic Weisbecker <fwei...@gmail.com>

LKML-Reference: <1257696066-4046-1-gi...@cs.helsinki.fi>
Signed-off-by: Ingo Molnar <mi...@elte.hu>