From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758054Ab0JEKjq (ORCPT ); Tue, 5 Oct 2010 06:39:46 -0400 Received: from mailout3.w1.samsung.com ([210.118.77.13]:27447 "EHLO mailout3.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752703Ab0JEKjp convert rfc822-to-8bit (ORCPT ); Tue, 5 Oct 2010 06:39:45 -0400 MIME-version: 1.0 Content-type: text/plain; charset=utf-8; format=flowed; delsp=yes Date: Tue, 05 Oct 2010 12:41:51 +0200 From: =?utf-8?B?TWljaGHFgiBOYXphcmV3aWN6?= Subject: Re: [PATCH 1/1] wait: using uninitialized member of wait queue In-reply-to: To: akpm@linux-foundation.org, torvalds@linux-foundation.org, Evgeny Kuznetsov Cc: mingo@elte.hu, gregkh@suse.de, a.p.zijlstra@chello.nl, xiaosuo@gmail.com, linux-kernel@vger.kernel.org, ext-eugeny.kuznetsov@nokia.com Message-id: Organization: Samsung Electronics Content-transfer-encoding: 8BIT User-Agent: Opera Mail/10.62 (Linux) References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 05 Oct 2010 10:47:57 +0200, Evgeny Kuznetsov wrote: > Member "flags" of "wait_queue_t" struct is used in several places in > kernel code without beeing initialized. "flags" is used in bitwise operations. ^^^^^^ -- "being" > If "flags" not initialized then unexpected behaviour may have place. > Incorrect flags maybe used later in code. > Struct "wait_queue_t" is initialized in function "init_wait()". But > "init_wait()" do not initialize "flag" member. ^^ -- does ^^^^ -- "flags" > Added initialization of "wait_queue_t.flags" with zero value into "init_wait". > diff --git a/include/linux/wait.h b/include/linux/wait.h > index 0836ccc..3efc9f3 100644 > --- a/include/linux/wait.h > +++ b/include/linux/wait.h > @@ -614,6 +614,7 @@ int wake_bit_function(wait_queue_t *wait, unsigned mode, int sync, void *key); > (wait)->private = current; \ > (wait)->func = autoremove_wake_function; \ > INIT_LIST_HEAD(&(wait)->task_list); \ > + (wait)->flags = 0; \ > } while (0) > /** I'd turn init_wait() into a static inline. Otherwise looks good to me. (Interestingly, init_wait() is used only in 3 places in the kernel and none uses flags.) -- Best regards, _ _ | Humble Liege of Serenely Enlightened Majesty of o' \,=./ `o | Computer Science, Michał "mina86" Nazarewicz (o o) +----[mina86*mina86.com]---[mina86*jabber.org]----ooO--(_)--Ooo--