[PATCH v2 4/4] selftests/livepatch: fix mem leaks in test-klp-shadow-vars

Yannick Cote
2020-06-03T18:21:53Z

In some cases, when an error occurs during testing and the main test
routine returns, a memory leak occurs via leaving previously registered
shadow variables allocated in the kernel as well as shadow_ptr list
elements. From now on, in case of error, remove all allocated shadow
variables and shadow_ptr struct elements.

Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Yannick Cote <ycote@redhat.com>
---
lib/livepatch/test_klp_shadow_vars.c | 43 ++++++++++++++++++++--------
1 file changed, 31 insertions(+), 12 deletions(-)

diff --git a/lib/livepatch/test_klp_shadow_vars.c b/lib/livepatch/test_klp_shadow_vars.c
index a49265e56917..b99116490858 100644
--- a/lib/livepatch/test_klp_shadow_vars.c
+++ b/lib/livepatch/test_klp_shadow_vars.c
@@ -170,6 +170,7 @@ static int test_klp_shadow_vars_init(void)
char *pndup[NUM_OBJS];
int nfields2[NUM_OBJS], *pnfields2[NUM_OBJS], **sv2[NUM_OBJS];
void **sv;
+ int ret;
int i;

ptr_id(NULL);
@@ -196,31 +197,39 @@ static int test_klp_shadow_vars_init(void)
sizeof(pnfields1[i]), GFP_KERNEL,
shadow_ctor, &pnfields1[i]);
}
- if (!sv1[i])
- return -ENOMEM;
+ if (!sv1[i]) {
+ ret = -ENOMEM;
+ goto out;
+ }

pnfields2[i] = &nfields2[i];
ptr_id(pnfields2[i]);
sv2[i] = shadow_alloc(&objs[i], SV_ID2, sizeof(pnfields2[i]),
GFP_KERNEL, shadow_ctor, &pnfields2[i]);
- if (!sv2[i])
- return -ENOMEM;
+ if (!sv2[i]) {
+ ret = -ENOMEM;
+ goto out;
+ }
}

/* pass 2: verify we find allocated svars and where they point to */
for (i = 0; i < NUM_OBJS; i++) {
/* check the "char" svar for all objects */
sv = shadow_get(&objs[i], SV_ID1);
- if (!sv)
- return -EINVAL;
+ if (!sv) {
+ ret = -EINVAL;
+ goto out;
+ }
if ((char **)sv == sv1[i] && *sv1[i] == pnfields1[i])
pr_info(" got expected PTR%d -> PTR%d result\n",
ptr_id(sv1[i]), ptr_id(*sv1[i]));

/* check the "int" svar for all objects */
sv = shadow_get(&objs[i], SV_ID2);
- if (!sv)
- return -EINVAL;
+ if (!sv) {
+ ret = -EINVAL;
+ goto out;
+ }
if ((int **)sv == sv2[i] && *sv2[i] == pnfields2[i])
pr_info(" got expected PTR%d -> PTR%d result\n",
ptr_id(sv2[i]), ptr_id(*sv2[i]));
@@ -233,8 +242,10 @@ static int test_klp_shadow_vars_init(void)

sv = shadow_get_or_alloc(&objs[i], SV_ID1, sizeof(pndup[i]),
GFP_KERNEL, shadow_ctor, &pndup[i]);
- if (!sv)
- return -EINVAL;
+ if (!sv) {
+ ret = -EINVAL;
+ goto out;
+ }
if ((char **)sv == sv1[i] && *sv1[i] == pnfields1[i])
pr_info(" got expected PTR%d -> PTR%d result\n",
ptr_id(sv1[i]), ptr_id(*sv1[i]));
@@ -251,8 +262,10 @@ static int test_klp_shadow_vars_init(void)
/* pass 5: check we still find <objs[*], SV_ID2> svar pairs */
for (i = 0; i < NUM_OBJS; i++) {
sv = shadow_get(&objs[i], SV_ID2); /* 'int' pairs */
- if (!sv)
- return -EINVAL;
+ if (!sv) {
+ ret = -EINVAL;
+ goto out;
+ }
if ((int **)sv == sv2[i] && *sv2[i] == pnfields2[i])
pr_info(" got expected PTR%d -> PTR%d result\n",
ptr_id(sv2[i]), ptr_id(*sv2[i]));
@@ -269,6 +282,12 @@ static int test_klp_shadow_vars_init(void)
free_ptr_list();

return 0;
+out:
+ shadow_free_all(SV_ID1, NULL); /* 'char' pairs */
+ shadow_free_all(SV_ID2, NULL); /* 'int' pairs */
+ free_ptr_list();
+
+ return ret;
}

static void test_klp_shadow_vars_exit(void)
--
2.25.4