From 972fdea2e6ece7578915d386a5447bc78d3fb8b8 Mon Sep 17 00:00:00 2001
From: Joe Perches <joe@perches.com>
Date: Mon, 29 Apr 2013 16:18:12 -0700
Subject: [PATCH] checkpatch: add check for reuse of krealloc arg
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On Thu, 2013-03-14 at 13:30 +0000, David Woodhouse wrote:
> If krealloc() returns NULL, it *doesn't* free the original. So any code
> of the form 'foo = krealloc(foo, …);' is almost certainly a bug.

So add a check for it to checkpatch.

Signed-off-by: Joe Perches <joe@perches.com>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Andy Whitcroft <apw@canonical.com>
Cc: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 scripts/checkpatch.pl | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 4de4bc48493b..a820249a3fce 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -3477,6 +3477,13 @@ sub process {
 			     "unnecessary cast may hide bugs, see http://c-faq.com/malloc/mallocnocast.html\n" . $herecurr);
 		}
 
+# check for krealloc arg reuse
+		if ($^V && $^V ge 5.10.0 &&
+		    $line =~ /\b($Lval)\s*\=\s*(?:$balanced_parens)?\s*krealloc\s*\(\s*\1\s*,/) {
+			WARN("KREALLOC_ARG_REUSE",
+			     "Reusing the krealloc arg is almost always a bug\n" . $herecurr);
+		}
+
 # check for alloc argument mismatch
 		if ($line =~ /\b(kcalloc|kmalloc_array)\s*\(\s*sizeof\b/) {
 			WARN("ALLOC_ARRAY_ARGS",