linux-kernel - [PATCH] lib/string.c: check for kmalloc() failure

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Date:   Thu, 17 Aug 2017 14:54:20 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     Andrew Morton <akpm@...ux-foundation.org>,
        Matthew Wilcox <mawilcox@...rosoft.com>
Cc:     Stephen Rothwell <sfr@...b.auug.org.au>,
        Kees Cook <keescook@...omium.org>,
        Matthew Wilcox <mawilcox@...rosoft.com>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
        Daniel Micay <danielmicay@...il.com>,
        linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: [PATCH] lib/string.c: check for kmalloc() failure

This is mostly to keep the number of static checker warnings down so
we can spot new bugs instead of them being drowned in noise.  This
function doesn't return normal kernel error codes but instead the return
value is used to display exactly which memory failed.  I chose -1 as
hopefully that's a helpful thing to print.

Signed-off-by: Dan Carpenter <dan.carpenter@...cle.com>

diff --git a/lib/string.c b/lib/string.c
index 661a6a6173c0..59e112cbcf22 100644
--- a/lib/string.c
+++ b/lib/string.c
@@ -1058,7 +1058,11 @@ EXPORT_SYMBOL(fortify_overflow);
 static __init int memset16_selftest(void)
 {
 	unsigned i, j, k;
-	u16 v, *p = kmalloc(256 * 2 * 2, GFP_KERNEL);
+	u16 v, *p;
+
+	p = kmalloc(256 * 2 * 2, GFP_KERNEL);
+	if (!p)
+		return -1;
 
 	for (i = 0; i < 256; i++) {
 		for (j = 0; j < 256; j++) {
@@ -1090,7 +1094,11 @@ static __init int memset16_selftest(void)
 static __init int memset32_selftest(void)
 {
 	unsigned i, j, k;
-	u32 v, *p = kmalloc(256 * 2 * 4, GFP_KERNEL);
+	u32 v, *p;
+
+	p = kmalloc(256 * 2 * 4, GFP_KERNEL);
+	if (!p)
+		return -1;
 
 	for (i = 0; i < 256; i++) {
 		for (j = 0; j < 256; j++) {
@@ -1122,7 +1130,11 @@ static __init int memset32_selftest(void)
 static __init int memset64_selftest(void)
 {
 	unsigned i, j, k;
-	u64 v, *p = kmalloc(256 * 2 * 8, GFP_KERNEL);
+	u64 v, *p;
+
+	p = kmalloc(256 * 2 * 8, GFP_KERNEL);
+	if (!p)
+		return -1;
 
 	for (i = 0; i < 256; i++) {
 		for (j = 0; j < 256; j++) {