[v14,10/22] selftests/vm: fix alloc_random_pkey() to make it really random

Commit Message

Ram Pai July 17, 2018, 1:49 p.m. UTC

alloc_random_pkey() was allocating the same pkey every time.
Not all pkeys were geting tested. fixed it.

cc: Dave Hansen <[e-mail]>
cc: Florian Weimer <[e-mail]>
Signed-off-by: Ram Pai <[e-mail]>
---
 tools/testing/selftests/vm/protection_keys.c |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)

Comments

Dave Hansen July 18, 2018, 3:45 p.m. UTC | #1

On 07/17/2018 06:49 AM, Ram Pai wrote:
> alloc_random_pkey() was allocating the same pkey every time.
> Not all pkeys were geting tested. fixed it.

This fixes a real issue but also unnecessarily munges whitespace.  If
you rev these again, please fix the munging.  Otherwise:

Acked-by: Dave Hansen <[e-mail]>
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Patch

diff --git a/tools/testing/selftests/vm/protection_keys.c b/tools/testing/selftests/vm/protection_keys.c
index 8fa4f74..2565b4c 100644
--- a/tools/testing/selftests/vm/protection_keys.c
+++ b/tools/testing/selftests/vm/protection_keys.c
@@ -24,6 +24,7 @@ 
 #define _GNU_SOURCE
 #include <errno.h>
 #include <linux/futex.h>
+#include <time.h>
 #include <sys/time.h>
 #include <sys/syscall.h>
 #include <string.h>
@@ -573,13 +574,15 @@  int alloc_random_pkey(void)
 	int alloced_pkeys[NR_PKEYS];
 	int nr_alloced = 0;
 	int random_index;
+
 	memset(alloced_pkeys, 0, sizeof(alloced_pkeys));
+	srand((unsigned int)time(NULL));
 
 	/* allocate every possible key and make a note of which ones we got */
 	max_nr_pkey_allocs = NR_PKEYS;
-	max_nr_pkey_allocs = 1;
 	for (i = 0; i < max_nr_pkey_allocs; i++) {
 		int new_pkey = alloc_pkey();
+
 		if (new_pkey < 0)
 			break;
 		alloced_pkeys[nr_alloced++] = new_pkey;
@@ -595,6 +598,7 @@  int alloc_random_pkey(void)
 	/* go through the allocated ones that we did not want and free them */
 	for (i = 0; i < nr_alloced; i++) {
 		int free_ret;
+
 		if (!alloced_pkeys[i])
 			continue;
 		free_ret = sys_pkey_free(alloced_pkeys[i]);