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

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Date:   Wed,  3 Jun 2020 14:20:58 -0400
From:   Yannick Cote <ycote@...hat.com>
To:     live-patching@...r.kernel.org
Cc:     linux-kselftest@...r.kernel.org, joe.lawrence@...hat.com,
        linux-kernel@...r.kernel.org, pmladek@...e.com, mbenes@...e.cz,
        kamalesh@...ux.vnet.ibm.com
Subject: [PATCH v2 4/4] selftests/livepatch: fix mem leaks in test-klp-shadow-vars

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@...e.com>
Reviewed-by: Kamalesh Babulal <kamalesh@...ux.vnet.ibm.com>
Acked-by: Miroslav Benes <mbenes@...e.cz>
Acked-by: Joe Lawrence <joe.lawrence@...hat.com>
Signed-off-by: Yannick Cote <ycote@...hat.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