[PATCH] perfcounter: fix zero or negative refresh delay

[PATCH] perfcounter: fix zero or negative refresh delay

[Frederic Weisbecker]

If perf top is executed with a zero value for the refresh rate,
we get a division by zero exception while computing samples_per_sec.

Also a zero refresh rate is not possible, neither do we want to
accept negative values.

[ Impact: fix division by zero in perf top ]

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
---
 Documentation/perf_counter/builtin-top.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/Documentation/perf_counter/builtin-top.c b/Documentation/perf_counter/builtin-top.c
index ff7e13c..b2f480b 100644
--- a/Documentation/perf_counter/builtin-top.c
+++ b/Documentation/perf_counter/builtin-top.c
@@ -693,6 +693,9 @@ int cmd_top(int argc, const char **argv, const char *prefix)
 		event_id[0] = 0;
 	}
 
+	if (delay_secs < 1)
+		delay_secs = 1;
+
 	for (counter = 0; counter < nr_counters; counter++) {
 		if (event_count[counter])
 			continue;
-- 
1.6.2.3

[tip:perfcounters/core] perf top: Fix zero or negative refresh delay

[tip-bot for Frederic Weisbecker]

Commit-ID:  2f335a02b3c816e77e7df1d15b12e3bbb8f4c8f0
Gitweb:     http://git.kernel.org/tip/2f335a02b3c816e77e7df1d15b12e3bbb8f4c8f0
Author:     Frederic Weisbecker <fweisbec@gmail.com>
AuthorDate: Fri, 5 Jun 2009 19:31:01 +0200
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Fri, 5 Jun 2009 20:42:53 +0200

perf top: Fix zero or negative refresh delay

If perf top is executed with a zero value for the refresh rate,
we get a division by zero exception while computing samples_per_sec.

Also a zero refresh rate is not possible, neither do we want to
accept negative values.

[ Impact: fix division by zero in perf top ]

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1244223061-5399-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>


---
 Documentation/perf_counter/builtin-top.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/Documentation/perf_counter/builtin-top.c b/Documentation/perf_counter/builtin-top.c
index ff7e13c..b2f480b 100644
--- a/Documentation/perf_counter/builtin-top.c
+++ b/Documentation/perf_counter/builtin-top.c
@@ -693,6 +693,9 @@ int cmd_top(int argc, const char **argv, const char *prefix)
 		event_id[0] = 0;
 	}
 
+	if (delay_secs < 1)
+		delay_secs = 1;
+
 	for (counter = 0; counter < nr_counters; counter++) {
 		if (event_count[counter])
 			continue;