Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754375AbWLYJlf (ORCPT ); Mon, 25 Dec 2006 04:41:35 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754376AbWLYJlf (ORCPT ); Mon, 25 Dec 2006 04:41:35 -0500 Received: from mtagate6.uk.ibm.com ([195.212.29.139]:46032 "EHLO mtagate6.uk.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754371AbWLYJle (ORCPT ); Mon, 25 Dec 2006 04:41:34 -0500 Date: Mon, 25 Dec 2006 11:41:32 +0200 From: Muli Ben-Yehuda To: Akinobu Mita Cc: Heiko Carstens , linux-kernel@vger.kernel.org, Hoang-Nam Nguyen , Christoph Raisch , akpm@osdl.org Subject: Re: [PATCH -mm] ehca: avoid crash on kthread_create() failure Message-ID: <20061225094132.GC2313@rhun.haifa.ibm.com> References: <20061219084248.GF4049@APFDCB5C> <20061221212202.GA23157@osiris.ibm.com> <20061225081257.GA3869@APFDCB5C> <20061225083023.GA5334@APFDCB5C> <20061225085551.GB2313@rhun.haifa.ibm.com> <20061225093557.GA5726@APFDCB5C> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20061225093557.GA5726@APFDCB5C> User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2305 Lines: 64 On Mon, Dec 25, 2006 at 06:35:57PM +0900, Akinobu Mita wrote: > On Mon, Dec 25, 2006 at 10:55:51AM +0200, Muli Ben-Yehuda wrote: > > This is correct because cct is allocated via alloc_percpu, which in > > turn calls kzalloc, which means cct->task is NULL by default, but it's > > a little too obscure for me. How about making it explicit? > > > > task = kthread_create(...) > > if (!IS_ERR(task)) > > cct->task = task; > > else > > cct->task = NULL; > > > > return cct->task; > > Subject: [PATCH -mm] ehca: avoid crash on kthread_create() failure (v3) > > This patch disallows invalid task_struct pointer returned by > kthread_create() to be written to percpu data to avoid crash. > > Cc: Heiko Carstens > Cc: Hoang-Nam Nguyen > Cc: Christoph Raisch > Signed-off-by: Akinobu Mita > > --- > drivers/infiniband/hw/ehca/ehca_irq.c | 11 ++++++++--- > 1 file changed, 8 insertions(+), 3 deletions(-) > > Index: 2.6-mm/drivers/infiniband/hw/ehca/ehca_irq.c > =================================================================== > --- 2.6-mm.orig/drivers/infiniband/hw/ehca/ehca_irq.c > +++ 2.6-mm/drivers/infiniband/hw/ehca/ehca_irq.c > @@ -606,15 +606,20 @@ static int comp_task(void *__cct) > static struct task_struct *create_comp_task(struct ehca_comp_pool *pool, > int cpu) > { > + struct task_struct *task; > struct ehca_cpu_comp_task *cct; > > cct = per_cpu_ptr(pool->cpu_comp_tasks, cpu); > spin_lock_init(&cct->task_lock); > INIT_LIST_HEAD(&cct->cq_list); > init_waitqueue_head(&cct->wait_queue); > - cct->task = kthread_create(comp_task, cct, "ehca_comp/%d", cpu); > + task = kthread_create(comp_task, cct, "ehca_comp/%d", cpu); > + if (!IS_ERR(task)) > + cct->task = task; > + else > + cct->task = NULL; > > - return cct->task; > + return task; This should be return cct->task, since we later test the return value of create_comp_task against NULL, e.g., in comp_poll_callback and ehca_create_comp_pool. Cheers, Muli - 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/