Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753837Ab2H2OYy (ORCPT ); Wed, 29 Aug 2012 10:24:54 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:38641 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753636Ab2H2OYw (ORCPT ); Wed, 29 Aug 2012 10:24:52 -0400 Subject: Re: [PATCH] fs/proc: Move kfree outside pde_unload_lock From: Eric Dumazet To: Alexey Dobriyan Cc: Nathan Zimmer , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Alexander Viro , David Woodhouse In-Reply-To: References: <1345653510-22000-1-git-send-email-nzimmer@sgi.com> <1345660110.5158.1969.camel@edumazet-glaptop> <1345671778.5158.2369.camel@edumazet-glaptop> <20120828203826.GA5868@p183.telecom.by> <1346213517.2522.2.camel@edumazet-glaptop> Content-Type: text/plain; charset="UTF-8" Date: Wed, 29 Aug 2012 07:24:48 -0700 Message-ID: <1346250288.2586.2.camel@edumazet-glaptop> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1985 Lines: 48 On Wed, 2012-08-29 at 16:50 +0300, Alexey Dobriyan wrote: > On Wed, Aug 29, 2012 at 7:11 AM, Eric Dumazet wrote: > > I'll polish this patch once LKS/LPC is over... > > It should oops in the following way (excuse Gmail please): > PDEO is removed from lists > ->pde_users is 0 > PDE won't be in purge queue -- no ->release while module is alive > > Current code removes PDEO and checks if PDE scheduled for removal atomically. > > proc_reg_release remove_proc_entry > > de->proc_fops = NULL; > release = pde_opener_del(inode, file); > rcu_read_lock(); > synchronize_rcu(); > fops = rcu_dereference(pde->proc_fops); > if (!fops) { > rcu_read_unlock(); > ---------------------------------- > /* NOP */ > while > (atomic_read(&de->pde_users)) > ... > /* NOP */ > > pde_openers_purge(de, &purge_queue); > /* NOP */ > while > (!list_empty(&purge_queue)) > ... > rmmod > > if (release) > release(inode, file) /* OOPS */ Fix should be trivial, proper module refcount for example. As I said, I would do that after LKS/LPC, there is no hurry. -- 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/