Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754372AbWLYJgK (ORCPT ); Mon, 25 Dec 2006 04:36:10 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754375AbWLYJgJ (ORCPT ); Mon, 25 Dec 2006 04:36:09 -0500 Received: from nz-out-0506.google.com ([64.233.162.237]:46671 "EHLO nz-out-0506.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754372AbWLYJgI (ORCPT ); Mon, 25 Dec 2006 04:36:08 -0500 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:date:from:to:cc:subject:message-id:mail-followup-to:references:mime-version:content-type:content-disposition:in-reply-to:user-agent; b=RC1XH9Dthvk8MYTvea9HEElr/nDNCE/BsaO0AfHU4NRBcSo4GEjUwfH7chPkcN3WPSe46dyEZlk4ibl0ZQjctTS57g7UTwQtGXO7vK8ipB1Kg0F6uKWXXDDdRZ3H11OagHMF2JEE1F7SrgHu6U3RmjZrd5vBYBlrBuY7kGYDV90= Date: Mon, 25 Dec 2006 18:35:57 +0900 From: Akinobu Mita To: Muli Ben-Yehuda 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: <20061225093557.GA5726@APFDCB5C> Mail-Followup-To: Akinobu Mita , Muli Ben-Yehuda , Heiko Carstens , linux-kernel@vger.kernel.org, Hoang-Nam Nguyen , Christoph Raisch , akpm@osdl.org References: <20061219084248.GF4049@APFDCB5C> <20061221212202.GA23157@osiris.ibm.com> <20061225081257.GA3869@APFDCB5C> <20061225083023.GA5334@APFDCB5C> <20061225085551.GB2313@rhun.haifa.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20061225085551.GB2313@rhun.haifa.ibm.com> User-Agent: Mutt/1.4.2.2i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2503 Lines: 72 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; } static void destroy_comp_task(struct ehca_comp_pool *pool, @@ -684,8 +689,10 @@ static int comp_pool_callback(struct not case CPU_UP_CANCELED: ehca_gen_dbg("CPU: %x (CPU_CANCELED)", cpu); cct = per_cpu_ptr(pool->cpu_comp_tasks, cpu); - kthread_bind(cct->task, any_online_cpu(cpu_online_map)); - destroy_comp_task(pool, cpu); + if (cct->task) { + kthread_bind(cct->task, any_online_cpu(cpu_online_map)); + destroy_comp_task(pool, cpu); + } break; case CPU_ONLINE: ehca_gen_dbg("CPU: %x (CPU_ONLINE)", cpu); - 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/