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Commit 3de29cab authored by Stephane Eranian's avatar Stephane Eranian Committed by Arnaldo Carvalho de Melo
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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: default avatarStephane Eranian <eranian@google.com>
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 6ba85cea

tools/perf/builtin-record.c

+5 −6
Original line number Diff line number Diff line
@@ -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;