perf record: Fix bug mismatch with -c option definition

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@davemloft.net>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <4bf11ae9.e88cd80a.06b0.ffffa8e3@mx.google.com>
Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 5 insertions, 6 deletions

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 0f467cf7aa72..b93573c7ac0b 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;