From: Frederic Weisbecker <fweisbec@gmail.com>
Date: Fri, 5 Jun 2009 17:31:01 +0000 (+0200)
Subject: perf top: Fix zero or negative refresh delay
X-Git-Tag: v2.6.31-rc1~383^2~52
X-Git-Url: https://openfabrics.org/gitweb/?a=commitdiff_plain;h=2f335a02b3c816e77e7df1d15b12e3bbb8f4c8f0;p=~emulex%2Finfiniband.git

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>
---

diff --git a/Documentation/perf_counter/builtin-top.c b/Documentation/perf_counter/builtin-top.c
index ff7e13c4647..b2f480b5a13 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;