Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756365AbXIRK2q (ORCPT ); Tue, 18 Sep 2007 06:28:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754956AbXIRK2j (ORCPT ); Tue, 18 Sep 2007 06:28:39 -0400 Received: from smtp2.linux-foundation.org ([207.189.120.14]:55056 "EHLO smtp2.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754949AbXIRK2j (ORCPT ); Tue, 18 Sep 2007 06:28:39 -0400 Date: Tue, 18 Sep 2007 03:27:27 -0700 From: Andrew Morton To: Alexey Dobriyan Cc: nadia.derbey@bull.net, linux-kernel@vger.kernel.org Subject: Re: 2.6.23-rc6-mm1: IPC: sleeping function called ... Message-Id: <20070918032727.c07aa521.akpm@linux-foundation.org> In-Reply-To: <20070918091728.GA6766@localhost.sw.ru> References: <20070918091728.GA6766@localhost.sw.ru> X-Mailer: Sylpheed 2.4.1 (GTK+ 2.8.17; x86_64-unknown-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1365 Lines: 47 On Tue, 18 Sep 2007 13:17:28 +0400 Alexey Dobriyan wrote: > I'm getting tons of this, and X fails to start > > CONFIG_SYSVIPC=y > CONFIG_SYSVIPC_SYSCTL=y > # CONFIG_PREEMPT_NONE is not set > # CONFIG_PREEMPT_VOLUNTARY is not set > CONFIG_PREEMPT=y > CONFIG_PREEMPT_BKL=y > CONFIG_DEBUG_PREEMPT=y > > BUG: sleeping function called from invalid context at kernel/rwsem.c:47 > in_atomic():1, irqs_disabled():0 OK, this fixes the locking here: --- a/ipc/util.c~ipc-integrate-ipc_checkid-into-ipc_lock-fix-2 +++ a/ipc/util.c @@ -295,7 +295,6 @@ int ipc_addid(struct ipc_ids* ids, struc spin_lock_init(&new->lock); new->deleted = 0; - rcu_read_lock(); spin_lock(&new->lock); return id; } @@ -691,7 +690,7 @@ struct kern_ipc_perm *ipc_lock(struct ip rcu_read_unlock(); return ERR_PTR(-EINVAL); } - + rcu_read_unlock(); return out; } _ But I'm not very confident in what's happening in there. The patches take away a _lot_ of the RCU locking, and it's unlear what's protecting the idr tree. Is it rcu, or is it the mutex? The code seems confused and the comments are all wrong. - 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/