From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756553AbYBJVcX (ORCPT ); Sun, 10 Feb 2008 16:32:23 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751140AbYBJVcI (ORCPT ); Sun, 10 Feb 2008 16:32:08 -0500 Received: from x35.xmailserver.org ([64.71.152.41]:59094 "EHLO x35.xmailserver.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752764AbYBJVcH (ORCPT ); Sun, 10 Feb 2008 16:32:07 -0500 X-AuthUser: davidel@xmailserver.org Date: Sun, 10 Feb 2008 13:32:01 -0800 (PST) From: Davide Libenzi X-X-Sender: davide@alien.or.mcafeemobile.com To: Linux Kernel Mailing List cc: Andrew Morton , Andrea Arcangeli , Vegard Nossum Subject: [patch] avoid kmemcheck warning in epoll Message-ID: X-GPG-FINGRPRINT: CFAE 5BEE FD36 F65E E640 56FE 0974 BF23 270F 474E X-GPG-PUBLIC_KEY: http://www.xmailserver.org/davidel.asc MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Epoll calls rb_set_parent(n, n) to initialize the rb-tree node, but rb_set_parent() accesses node's pointer in its code. This creates a warning in kmemcheck (reported by Vegard Nossum) about an uninitialized memory access. The warning is harmless since the following rb-tree node insert is going to overwrite the node data. In any case I think it's better to not have that happening at all, and fix it by properly initializing the data. Signed-off-by: Davide Libenzi - Davide --- fs/eventpoll.c | 2 +- include/linux/rbtree.h | 12 ++++++++++++ 2 files changed, 13 insertions(+), 1 deletion(-) Index: linux-2.6.mod/fs/eventpoll.c =================================================================== --- linux-2.6.mod.orig/fs/eventpoll.c 2008-02-10 12:36:20.000000000 -0800 +++ linux-2.6.mod/fs/eventpoll.c 2008-02-10 12:50:41.000000000 -0800 @@ -260,7 +260,7 @@ /* Special initialization for the RB tree node to detect linkage */ static inline void ep_rb_initnode(struct rb_node *n) { - rb_set_parent(n, n); + rb_init_node(n, n); } /* Removes a node from the RB tree and marks it for a fast is-linked check */ Index: linux-2.6.mod/include/linux/rbtree.h =================================================================== --- linux-2.6.mod.orig/include/linux/rbtree.h 2008-02-10 12:36:13.000000000 -0800 +++ linux-2.6.mod/include/linux/rbtree.h 2008-02-10 12:51:57.000000000 -0800 @@ -112,6 +112,18 @@ struct rb_node *rb_node; }; +/** + * rb_init_node - Initializes the node internal data + * + * @node: Pointer to the RB-Tree node + * @parent: Pointer to the parent node, or NULL + * + */ +static inline void rb_init_node(struct rb_node *node, struct rb_node *parent) +{ + node->rb_parent_color = (unsigned long) parent; + node->rb_left = node->rb_right = NULL; +} #define rb_parent(r) ((struct rb_node *)((r)->rb_parent_color & ~3)) #define rb_color(r) ((r)->rb_parent_color & 1)