[PATCH] perf tests: Do not use sizeof on pointer type

[PATCH] perf tests: Do not use sizeof on pointer type

[Vaishali Thakkar]

Using sizeof on a malloced pointer type will return the wordsize
which can often cause one to allocate a buffer much smaller than
it is needed. So, here do not use sizeof on pointer type.

Note that this has no effect on runtime because 'dsos' is a
pointer to a pointer.

Problem found using Coccinelle.

Signed-off-by: Vaishali Thakkar <vaishali.thakkar@oracle.com>
---
 tools/perf/tests/dso-data.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/tests/dso-data.c b/tools/perf/tests/dso-data.c
index dc673ff..8cf0d9e 100644
--- a/tools/perf/tests/dso-data.c
+++ b/tools/perf/tests/dso-data.c
@@ -202,7 +202,7 @@ static int dsos__create(int cnt, int size)
 {
 	int i;
 
-	dsos = malloc(sizeof(dsos) * cnt);
+	dsos = malloc(sizeof(*dsos) * cnt);
 	TEST_ASSERT_VAL("failed to alloc dsos array", dsos);
 
 	for (i = 0; i < cnt; i++) {
-- 
2.1.4

Re: [PATCH] perf tests: Do not use sizeof on pointer type

[Arnaldo Carvalho de Melo]

Em Thu, Apr 28, 2016 at 10:16:57PM +0530, Vaishali Thakkar escreveu:
> Using sizeof on a malloced pointer type will return the wordsize
> which can often cause one to allocate a buffer much smaller than
> it is needed. So, here do not use sizeof on pointer type.
> 
> Note that this has no effect on runtime because 'dsos' is a
> pointer to a pointer.
> 
> Problem found using Coccinelle.

Thanks, applied.

- Arnaldo

[tip:perf/core] perf tests: Do not use sizeof on pointer type

[tip-bot for Vaishali Thakkar]

Commit-ID:  ca7ce82a280a65c377c24c95c29b1dec6e80b428
Gitweb:     http://git.kernel.org/tip/ca7ce82a280a65c377c24c95c29b1dec6e80b428
Author:     Vaishali Thakkar <vaishali.thakkar@oracle.com>
AuthorDate: Thu, 28 Apr 2016 22:16:57 +0530
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Thu, 28 Apr 2016 15:37:52 -0300

perf tests: Do not use sizeof on pointer type

Using sizeof on a malloced pointer type will return the wordsize which
can often cause one to allocate a buffer much smaller than it is needed.
So, here do not use sizeof on pointer type.

Note that this has no effect on runtime because 'dsos' is a pointer to a
pointer.

Problem found using Coccinelle.

Signed-off-by: Vaishali Thakkar <vaishali.thakkar@oracle.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1461862017-23358-1-git-send-email-vaishali.thakkar@oracle.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/tests/dso-data.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/tests/dso-data.c b/tools/perf/tests/dso-data.c
index dc673ff..8cf0d9e 100644
--- a/tools/perf/tests/dso-data.c
+++ b/tools/perf/tests/dso-data.c
@@ -202,7 +202,7 @@ static int dsos__create(int cnt, int size)
 {
 	int i;
 
-	dsos = malloc(sizeof(dsos) * cnt);
+	dsos = malloc(sizeof(*dsos) * cnt);
 	TEST_ASSERT_VAL("failed to alloc dsos array", dsos);
 
 	for (i = 0; i < cnt; i++) {