From: Julia Lawall <Julia.Lawall@lip6.fr>
Date: Sat, 14 Jul 2012 16:43:08 +0000 (+0200)
Subject: arch/x86/kernel/kdebugfs.c: Ensure a consistent return value in error case
X-Git-Tag: v3.6-rc2~36^2~1
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=41fb433b63cc4745f4918fdaf295763da5ca826c;p=linux.git

arch/x86/kernel/kdebugfs.c: Ensure a consistent return value in error case

Typically, the return value desired for the failure of a
function with an integer return value is a negative integer.  In
these cases, the return value is sometimes a negative integer
and sometimes 0, due to a subsequent initialization of the
return variable within the loop.

A simplified version of the semantic match that finds this
problem is: (http://coccinelle.lip6.fr/)

//<smpl>
@r exists@
identifier ret;
position p;
constant C;
expression e1,e3,e4;
statement S;
@@

ret = -C
... when != ret = e3
    when any
if@p (...) S
... when any
if (\(ret != 0\|ret < 0\|ret > 0\) || ...) { ... return ...; }
... when != ret = e3
    when any
*if@p (...)
{
  ... when != ret = e4
  return ret;
}
//</smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Link: http://lkml.kernel.org/r/1342284188-19176-7-git-send-email-Julia.Lawall@lip6.fr
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---

diff --git a/arch/x86/kernel/kdebugfs.c b/arch/x86/kernel/kdebugfs.c
index 1d5d31ea686b..dc1404bf8e4b 100644
--- a/arch/x86/kernel/kdebugfs.c
+++ b/arch/x86/kernel/kdebugfs.c
@@ -107,7 +107,7 @@ static int __init create_setup_data_nodes(struct dentry *parent)
 {
 	struct setup_data_node *node;
 	struct setup_data *data;
-	int error = -ENOMEM;
+	int error;
 	struct dentry *d;
 	struct page *pg;
 	u64 pa_data;
@@ -121,8 +121,10 @@ static int __init create_setup_data_nodes(struct dentry *parent)
 
 	while (pa_data) {
 		node = kmalloc(sizeof(*node), GFP_KERNEL);
-		if (!node)
+		if (!node) {
+			error = -ENOMEM;
 			goto err_dir;
+		}
 
 		pg = pfn_to_page((pa_data+sizeof(*data)-1) >> PAGE_SHIFT);
 		if (PageHighMem(pg)) {