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From: Arnaldo Carvalho de Melo on 17 May 2010 11:50
From: Stephane Eranian <eranian(a)google.com>

The -c option defines the user requested sampling period. It was implemented
using an unsigned int variable but the type of the option was OPT_LONG. Thus,
the option parser was overwriting memory belonging to other variables, namely
the mmap_pages leading to a zero page sampling buffer. The bug was exposed only
when compiling at -O0, probably because the compiler was padding variables at
higher optimization levels.

This patch fixes this problem by declaring user_interval as u64. This also
avoids wrap-around issues for large period on 32-bit systems.

Commiter note:

Made it use OPT_U64(user_interval) after implementing OPT_U64 in the
previous patch.

Cc: David S. Miller <davem(a)davemloft.net>
Cc: Frédéric Weisbecker <fweisbec(a)gmail.com>
Cc: Ingo Molnar <mingo(a)elte.hu>
Cc: Paul Mackerras <paulus(a)samba.org>
Cc: Peter Zijlstra <peterz(a)infradead.org>
LKML-Reference: <4bf11ae9.e88cd80a.06b0.ffffa8e3(a)mx.google.com>
Signed-off-by: Stephane Eranian <eranian(a)google.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme(a)redhat.com>
---
tools/perf/builtin-record.c | 11 +++++------
1 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 0f467cf..b93573c 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -33,8 +33,8 @@ enum write_mode_t {

static int *fd[MAX_NR_CPUS][MAX_COUNTERS];

-static unsigned int user_interval = UINT_MAX;
-static long default_interval = 0;
+static u64 user_interval = ULLONG_MAX;
+static u64 default_interval = 0;

static int nr_cpus = 0;
static unsigned int page_size;
@@ -268,7 +268,7 @@ static void create_counter(int counter, int cpu)
* it a weak assumption overridable by the user.
*/
if (!attr->sample_period || (user_freq != UINT_MAX &&
- user_interval != UINT_MAX)) {
+ user_interval != ULLONG_MAX)) {
if (freq) {
attr->sample_type |= PERF_SAMPLE_PERIOD;
attr->freq = 1;
@@ -817,8 +817,7 @@ static const struct option options[] = {
"CPU to profile on"),
OPT_BOOLEAN('f', "force", &force,
"overwrite existing data file (deprecated)"),
- OPT_LONG('c', "count", &user_interval,
- "event period to sample"),
+ OPT_U64('c', "count", &user_interval, "event period to sample"),
OPT_STRING('o', "output", &output_name, "file",
"output file name"),
OPT_BOOLEAN('i', "no-inherit", &no_inherit,
@@ -901,7 +900,7 @@ int cmd_record(int argc, const char **argv, const char *prefix __used)
if (!event_array)
return -ENOMEM;

- if (user_interval != UINT_MAX)
+ if (user_interval != ULLONG_MAX)
default_interval = user_interval;
if (user_freq != UINT_MAX)
freq = user_freq;
--
1.6.2.5

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