From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 383D1C04AB6 for ; Fri, 31 May 2019 09:26:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 085BA266C0 for ; Fri, 31 May 2019 09:26:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726275AbfEaJ0r (ORCPT ); Fri, 31 May 2019 05:26:47 -0400 Received: from szxga06-in.huawei.com ([45.249.212.32]:45052 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726240AbfEaJ0r (ORCPT ); Fri, 31 May 2019 05:26:47 -0400 Received: from DGGEMS403-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id 6C9C2CF031826829C3CD; Fri, 31 May 2019 17:26:43 +0800 (CST) Received: from [127.0.0.1] (10.177.19.180) by DGGEMS403-HUB.china.huawei.com (10.3.19.203) with Microsoft SMTP Server id 14.3.439.0; Fri, 31 May 2019 17:26:37 +0800 Subject: Re: [PATCH] crypto: pcrypt: Fix possible deadlock in padata_sysfs_release To: Steffen Klassert , Herbert Xu , "David S. Miller" CC: , , Hulk Robot References: <20190531092923.4874-1-wangkefeng.wang@huawei.com> From: Kefeng Wang Message-ID: <1b71b136-3501-db1c-834b-ba7ed1431f4d@huawei.com> Date: Fri, 31 May 2019 17:23:51 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.3.1 MIME-Version: 1.0 In-Reply-To: <20190531092923.4874-1-wangkefeng.wang@huawei.com> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Content-Language: en-US X-Originating-IP: [10.177.19.180] X-CFilter-Loop: Reflected Sender: linux-crypto-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org On 2019/5/31 17:29, Kefeng Wang wrote: > There is a deadlock issue in pcrypt_init_padata(), > > pcrypt_init_padata() > cpus_read_lock() > padata_free() > padata_sysfs_release() > cpus_read_lock() > > Narrow rcu_read_lock/unlock() and move put_online_cpus() > before padata_free() to fix it. > > Reported-by: Hulk Robot > Signed-off-by: Kefeng Wang > --- > crypto/pcrypt.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/crypto/pcrypt.c b/crypto/pcrypt.c > index 0e9ce329fd47..662228b48b70 100644 > --- a/crypto/pcrypt.c > +++ b/crypto/pcrypt.c > @@ -407,13 +407,14 @@ static int pcrypt_init_padata(struct padata_pcrypt *pcrypt, > int ret = -ENOMEM; > struct pcrypt_cpumask *mask; > > - get_online_cpus(); > > pcrypt->wq = alloc_workqueue("%s", WQ_MEM_RECLAIM | WQ_CPU_INTENSIVE, > 1, name); > if (!pcrypt->wq) > goto err; > > + get_online_cpus(); > + > pcrypt->pinst = padata_alloc_possible(pcrypt->wq); > if (!pcrypt->pinst) Oh, forget to add put_online_cpus in this error path, will resend v2 if there is no comment. > goto err_destroy_workqueue; > @@ -448,12 +449,11 @@ static int pcrypt_init_padata(struct padata_pcrypt *pcrypt, > free_cpumask_var(mask->mask); > kfree(mask); > err_free_padata: > + put_online_cpus(); > padata_free(pcrypt->pinst); > err_destroy_workqueue: > destroy_workqueue(pcrypt->wq); > err: > - put_online_cpus(); > - > return ret; > } >