From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx123.postini.com [74.125.245.123]) by kanga.kvack.org (Postfix) with SMTP id A0AE96B0033 for ; Tue, 6 Aug 2013 20:19:06 -0400 (EDT) Received: by mail-pa0-f46.google.com with SMTP id fa1so1450151pad.33 for ; Tue, 06 Aug 2013 17:19:05 -0700 (PDT) In-Reply-To: <20130807000154.GA3507@z460> References: <20130807000154.GA3507@z460> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----N00HUACV1W9UY64SK4X6964RZN431A" Subject: Re: [PATCH] mm: numa: fix NULL pointer dereference From: zhouxinxing Date: Wed, 07 Aug 2013 08:19:22 +0800 Message-ID: <395f1269-2a31-44be-90ff-d2c470d64ca7@email.android.com> Sender: owner-linux-mm@kvack.org List-ID: To: Mauro Dreissig , linux-mm@kvack.org ------N00HUACV1W9UY64SK4X6964RZN431A Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Is it possible to check pol if it is equal to NULL prior to access to mode field? Mauro Dreissig wrote: >From: Mauro Dreissig > >The "pol->mode" field is accessed even when no mempolicy >is assigned to the "pol" variable. > >Signed-off-by: Mauro Dreissig >--- > mm/mempolicy.c | 12 ++++++++---- > 1 file changed, 8 insertions(+), 4 deletions(-) > >diff --git a/mm/mempolicy.c b/mm/mempolicy.c >index 6b1d426..105fff0 100644 >--- a/mm/mempolicy.c >+++ b/mm/mempolicy.c >@@ -127,12 +127,16 @@ static struct mempolicy *get_task_policy(struct >task_struct *p) > > if (!pol) { > node = numa_node_id(); >- if (node != NUMA_NO_NODE) >+ if (node != NUMA_NO_NODE) { > pol = &preferred_node_policy[node]; > >- /* preferred_node_policy is not initialised early in boot */ >- if (!pol->mode) >- pol = NULL; >+ /* >+ * preferred_node_policy is not initialised early >+ * in boot >+ */ >+ if (!pol->mode) >+ pol = NULL; >+ } > } > > return pol; >-- >1.8.1.2 > >-- >To unsubscribe, send a message with 'unsubscribe linux-mm' in >the body to majordomo@kvack.org. For more info on Linux MM, >see: http://www.linux-mm.org/ . >Don't email: email@kvack.org -- Sent from my Android device with Gmail Plus. Please excuse my brevity. ------N00HUACV1W9UY64SK4X6964RZN431A Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: 8bit Is it possible to check pol if it is equal to NULL prior to access to mode field?

Mauro Dreissig <mukadr@gmail.com> wrote:
From: Mauro Dreissig <mukadr@gmail.com>

The "pol->mode" field is accessed even when no mempolicy
is assigned to the "pol" variable.

Signed-off-by: Mauro Dreissig <mukadr@gmail.com>
---
mm/mempolicy.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 6b1d426..105fff0 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -127,12 +127,16 @@ static struct mempolicy *get_task_policy(struct task_struct *p)

 if (!pol) {
  node = numa_node_id();
-  if (node != NUMA_NO_NODE)
+  if (node != NUMA_NO_NODE) {
   pol = &preferred_node_policy[node];

-  /* preferred_node_policy is not initialised early in boot */
-  if (!pol->mode)
-   pol = NULL;
+   /*
+    * preferred_node_policy
is not initialised early
+    * in boot
+    */
+   if (!pol->mode)
+    pol = NULL;
+  }
 }

 return pol;

--
Sent from my Android device with Gmail Plus. Please excuse my brevity. ------N00HUACV1W9UY64SK4X6964RZN431A-- -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org