linux-kernel - [PATCH 2/4] livepatch: Handle failing allocation of shadow variables in the selftest

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Message-Id: <20190116161720.796-3-pmladek@suse.com>
Date:   Wed, 16 Jan 2019 17:17:18 +0100
From:   Petr Mladek <pmladek@...e.com>
To:     Jiri Kosina <jikos@...nel.org>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        Miroslav Benes <mbenes@...e.cz>
Cc:     Jason Baron <jbaron@...mai.com>,
        Joe Lawrence <joe.lawrence@...hat.com>,
        Evgenii Shatokhin <eshatokhin@...tuozzo.com>,
        live-patching@...r.kernel.org, linux-kernel@...r.kernel.org,
        Petr Mladek <pmladek@...e.com>
Subject: [PATCH 2/4] livepatch: Handle failing allocation of shadow variables in the selftest

Do not dereference pointers to the shadow variables when either
klp_shadow_alloc() or klp_shadow_get() fail.

There is no need to check the other locations explicitly. The test
would fail if any allocation fails. And the existing messages, printed
during the test, provide enough information to debug eventual problems.

Signed-off-by: Petr Mladek <pmladek@...e.com>
---
 lib/livepatch/test_klp_shadow_vars.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/lib/livepatch/test_klp_shadow_vars.c b/lib/livepatch/test_klp_shadow_vars.c
index 02f892f941dc..55e6820430dc 100644
--- a/lib/livepatch/test_klp_shadow_vars.c
+++ b/lib/livepatch/test_klp_shadow_vars.c
@@ -162,15 +162,15 @@ static int test_klp_shadow_vars_init(void)
 	 * to expected data.
 	 */
 	ret = shadow_get(obj, id);
-	if (ret == sv1 && *sv1 == &var1)
+	if (ret && ret == sv1 && *sv1 == &var1)
 		pr_info("  got expected PTR%d -> PTR%d result\n",
 			ptr_id(sv1), ptr_id(*sv1));
 	ret = shadow_get(obj + 1, id);
-	if (ret == sv2 && *sv2 == &var2)
+	if (ret && ret == sv2 && *sv2 == &var2)
 		pr_info("  got expected PTR%d -> PTR%d result\n",
 			ptr_id(sv2), ptr_id(*sv2));
 	ret = shadow_get(obj, id + 1);
-	if (ret == sv3 && *sv3 == &var3)
+	if (ret && ret == sv3 && *sv3 == &var3)
 		pr_info("  got expected PTR%d -> PTR%d result\n",
 			ptr_id(sv3), ptr_id(*sv3));
 
@@ -180,7 +180,7 @@ static int test_klp_shadow_vars_init(void)
 	 */
 	sv4 = shadow_get_or_alloc(obj + 2, id, size, gfp_flags, shadow_ctor, &var4);
 	ret = shadow_get_or_alloc(obj + 2, id, size, gfp_flags, shadow_ctor, &var4);
-	if (ret == sv4 && *sv4 == &var4)
+	if (ret && ret == sv4 && *sv4 == &var4)
 		pr_info("  got expected PTR%d -> PTR%d result\n",
 			ptr_id(sv4), ptr_id(*sv4));
 
-- 
2.13.7