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=-16.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 30FA3C11F68 for ; Tue, 29 Jun 2021 17:27:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1432961D90 for ; Tue, 29 Jun 2021 17:27:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234375AbhF2R3c (ORCPT ); Tue, 29 Jun 2021 13:29:32 -0400 Received: from mail.kernel.org ([198.145.29.99]:33986 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233106AbhF2R3a (ORCPT ); Tue, 29 Jun 2021 13:29:30 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id CB1C561D8E; Tue, 29 Jun 2021 17:27:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1624987623; bh=Fiyq8xQDH18p8i42/BBHJsOdmil86LfKlHbmik4QPqw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=dEkr2G062XoUHkfTNTd+ZcmImQUgBmpzv8OzOKQQysYTfcTC/TfvKJTgJj9sufFdW sD15/6ICokwg14m4PEOVikUlyhXUhvJCacA6GEfcLQdGwO6Pvt0Awg0CTfg51ohpDz sNK6saZ+0Cm8G5OyTnD7/galyNEE/5Jkv5LQIOhdBXM6gEowO7fb34kOPEUmWhmaWT WpD3BvyYX1Fv64U0C4T8w5anoh4s7Kh8HU/gzZBpO289iGQV5KcwVzqvw9IVH0LOo6 ViyWOSN42cNna8np4bhIuLJ8G4/OYrCNcukBTVZX5NaUEU9Ob/epK9OAiqqJ/m2cxP gvJSt641F/nQw== Date: Tue, 29 Jun 2021 20:27:00 +0300 From: Jarkko Sakkinen To: Saubhik Mukherjee Cc: peterhuewe@gmx.de, jgg@ziepe.ca, linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org, ldv-project@linuxtesting.org, andrianov@ispras.ru Subject: Re: [PATCH] char: tpm: vtpm_proxy: Fix race in init Message-ID: <20210629172700.yxqnedbayumo5f24@kernel.org> References: <20210623132226.140341-1-saubhik.mukherjee@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210623132226.140341-1-saubhik.mukherjee@gmail.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 23, 2021 at 06:52:26PM +0530, Saubhik Mukherjee wrote: > vtpm_module_init calls vtpmx_init which calls misc_register. The file > operations callbacks are registered. So, vtpmx_fops_ioctl can execute in > parallel with rest of vtpm_module_init. vtpmx_fops_ioctl calls > vtpmx_ioc_new_dev, which calls vtpm_proxy_create_device, which calls > vtpm_proxy_work_start, which could read uninitialized workqueue. > > To avoid this, create workqueue before vtpmx init. > > Found by Linux Driver Verification project (linuxtesting.org). > > Signed-off-by: Saubhik Mukherjee > --- > drivers/char/tpm/tpm_vtpm_proxy.c | 19 +++++++++---------- > 1 file changed, 9 insertions(+), 10 deletions(-) > > diff --git a/drivers/char/tpm/tpm_vtpm_proxy.c b/drivers/char/tpm/tpm_vtpm_proxy.c > index 91c772e38bb5..225dfa026a8f 100644 > --- a/drivers/char/tpm/tpm_vtpm_proxy.c > +++ b/drivers/char/tpm/tpm_vtpm_proxy.c > @@ -697,23 +697,22 @@ static int __init vtpm_module_init(void) > { > int rc; > > - rc = vtpmx_init(); > - if (rc) { > - pr_err("couldn't create vtpmx device\n"); > - return rc; > - } > - > workqueue = create_workqueue("tpm-vtpm"); > if (!workqueue) { > pr_err("couldn't create workqueue\n"); > - rc = -ENOMEM; > - goto err_vtpmx_cleanup; > + return -ENOMEM; > + } > + > + rc = vtpmx_init(); > + if (rc) { > + pr_err("couldn't create vtpmx device\n"); > + goto err_destroy_workqueue; > } > > return 0; > > -err_vtpmx_cleanup: > - vtpmx_cleanup(); > +err_destroy_workqueue: > + destroy_workqueue(workqueue); > > return rc; > } > -- > 2.30.2 > > Reviewed-by: Jarkko Sakkinen /Jarkko