Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754932AbXE3NrR (ORCPT ); Wed, 30 May 2007 09:47:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754383AbXE3NrB (ORCPT ); Wed, 30 May 2007 09:47:01 -0400 Received: from wr-out-0506.google.com ([64.233.184.235]:16333 "EHLO wr-out-0506.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754400AbXE3NrA (ORCPT ); Wed, 30 May 2007 09:47:00 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:user-agent:mime-version:to:cc:subject:references:in-reply-to:x-enigmail-version:content-type:content-transfer-encoding; b=En5SM0FK8pFplozkNiFUYO2TlevPDFGi9ft7vJnmSbE3CboRmOM1DmrZcJe8HYM5Ia1TKE5O5fykd6+hPH84vB/i+0/ysiAXv/LHuSmVhZfGCHE1WtdgxBQXqXiWwjNCGvAjEaeayYRXAwVqydfzk03UrzBZl4k4X8IDdVyMfiU= Message-ID: <465D800B.2050502@gmail.com> Date: Wed, 30 May 2007 22:45:47 +0900 From: Tejun Heo User-Agent: Thunderbird 2.0.0.0 (X11/20070326) MIME-Version: 1.0 To: Cornelia Huck CC: gregkh@suse.de, dmitry.torokhov@gmail.com, oneukum@suse.de, rpurdie@rpsys.net, stern@rowland.harvard.edu, maneesh@in.ibm.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH 4/6] sysfs: use sysfs_lock to protect the sysfs_dirent tree References: <11803701861778-git-send-email-htejun@gmail.com> <1180370187803-git-send-email-htejun@gmail.com> <20070530133329.4a10a892@gondolin.boeblingen.de.ibm.com> In-Reply-To: <20070530133329.4a10a892@gondolin.boeblingen.de.ibm.com> X-Enigmail-Version: 0.95.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1089 Lines: 36 Cornelia Huck wrote: > On Tue, 29 May 2007 01:36:27 +0900, > Tejun Heo wrote: > >> @@ -795,6 +822,8 @@ static int sysfs_readdir(struct file * f >> i++; >> /* fallthrough */ >> default: >> + spin_lock(&sysfs_lock); >> + >> pos = &parent_sd->s_children; >> while (*pos != cursor) >> pos = &(*pos)->s_sibling; >> @@ -827,6 +856,8 @@ static int sysfs_readdir(struct file * f >> /* put cursor back in */ >> cursor->s_sibling = *pos; >> *pos = cursor; >> + >> + spin_unlock(&sysfs_lock); >> } >> return 0; >> } > > Here's the cause of the "sleeping function called" I saw. filldir() is > called under sysfs_lock, but calls copy_to_user()... This means you > can't use sysfs_lock for protection here. Ouch, right. I think we can get away with a temp buffer there. Thanks. -- tejun - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/