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=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 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 D2494C4361B for ; Mon, 7 Dec 2020 10:54:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 965FB20882 for ; Mon, 7 Dec 2020 10:54:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726467AbgLGKyP convert rfc822-to-8bit (ORCPT ); Mon, 7 Dec 2020 05:54:15 -0500 Received: from relay8-d.mail.gandi.net ([217.70.183.201]:34161 "EHLO relay8-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725842AbgLGKyO (ORCPT ); Mon, 7 Dec 2020 05:54:14 -0500 X-Originating-IP: 109.220.208.103 Received: from xps13 (lfbn-tou-1-1617-103.w109-220.abo.wanadoo.fr [109.220.208.103]) (Authenticated sender: miquel.raynal@bootlin.com) by relay8-d.mail.gandi.net (Postfix) with ESMTPSA id 30BCA1BF20E; Mon, 7 Dec 2020 10:53:31 +0000 (UTC) Date: Mon, 7 Dec 2020 11:53:30 +0100 From: Miquel Raynal To: Xiaoming Ni Cc: , , , , , , , , Subject: Re: ping // [PATCH] mtd:cfi_cmdset_0002: fix atomic sleep bug when CONFIG_MTD_XIP=y Message-ID: <20201207115228.0a6de398@xps13> In-Reply-To: References: <20201127130731.99270-1-nixiaoming@huawei.com> Organization: Bootlin X-Mailer: Claws Mail 3.17.4 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Xiaoming, Xiaoming Ni wrote on Mon, 7 Dec 2020 18:48:33 +0800: > ping > > On 2020/11/27 21:07, Xiaoming Ni wrote: > > When CONFIG_MTD_XIP=y, local_irq_disable() is called in xip_disable(). > > To avoid sleep in interrupt context, we need to call local_irq_enable() > > before schedule(). > > > > The problem call stack is as follows: > > bug1: > > do_write_oneword_retry() > > xip_disable() > > local_irq_disable() > > do_write_oneword_once() > > schedule() > > bug2: > > do_write_buffer() > > xip_disable() > > local_irq_disable() > > do_write_buffer_wait() > > schedule() > > bug3: > > do_erase_chip() > > xip_disable() > > local_irq_disable() > > schedule() > > bug4: > > do_erase_oneblock() > > xip_disable() > > local_irq_disable() > > schedule() > > > > Fixes: 02b15e343aee ("[MTD] XIP for AMD CFI flash.") > > Cc: stable@vger.kernel.org # v2.6.13 > > Signed-off-by: Xiaoming Ni > > --- > > drivers/mtd/chips/cfi_cmdset_0002.c | 16 ++++++++++++++++ > > 1 file changed, 16 insertions(+) > > > > diff --git a/drivers/mtd/chips/cfi_cmdset_0002.c b/drivers/mtd/chips/cfi_cmdset_0002.c > > index a1f3e1031c3d..12c3776f093a 100644 > > --- a/drivers/mtd/chips/cfi_cmdset_0002.c > > +++ b/drivers/mtd/chips/cfi_cmdset_0002.c > > @@ -1682,7 +1682,11 @@ static int __xipram do_write_oneword_once(struct map_info *map, > > set_current_state(TASK_UNINTERRUPTIBLE); > > add_wait_queue(&chip->wq, &wait); > > mutex_unlock(&chip->mutex); > > + if (IS_ENABLED(CONFIG_MTD_XIP)) > > + local_irq_enable(); > > schedule(); > > + if (IS_ENABLED(CONFIG_MTD_XIP)) > > + local_irq_disable(); The fix really seems strange to me. I will let Vignesh decide but I think we should consider updating/fixing xip_disable instead. > > remove_wait_queue(&chip->wq, &wait); > > timeo = jiffies + (HZ / 2); /* FIXME */ > > mutex_lock(&chip->mutex); > > @@ -1962,7 +1966,11 @@ static int __xipram do_write_buffer_wait(struct map_info *map, > > set_current_state(TASK_UNINTERRUPTIBLE); > > add_wait_queue(&chip->wq, &wait); > > mutex_unlock(&chip->mutex); > > + if (IS_ENABLED(CONFIG_MTD_XIP)) > > + local_irq_enable(); > > schedule(); > > + if (IS_ENABLED(CONFIG_MTD_XIP)) > > + local_irq_disable(); > > remove_wait_queue(&chip->wq, &wait); > > timeo = jiffies + (HZ / 2); /* FIXME */ > > mutex_lock(&chip->mutex); > > @@ -2461,7 +2469,11 @@ static int __xipram do_erase_chip(struct map_info *map, struct flchip *chip) > > set_current_state(TASK_UNINTERRUPTIBLE); > > add_wait_queue(&chip->wq, &wait); > > mutex_unlock(&chip->mutex); > > + if (IS_ENABLED(CONFIG_MTD_XIP)) > > + local_irq_enable(); > > schedule(); > > + if (IS_ENABLED(CONFIG_MTD_XIP)) > > + local_irq_disable(); > > remove_wait_queue(&chip->wq, &wait); > > mutex_lock(&chip->mutex); > > continue; > > @@ -2560,7 +2572,11 @@ static int __xipram do_erase_oneblock(struct map_info *map, struct flchip *chip, > > set_current_state(TASK_UNINTERRUPTIBLE); > > add_wait_queue(&chip->wq, &wait); > > mutex_unlock(&chip->mutex); > > + if (IS_ENABLED(CONFIG_MTD_XIP)) > > + local_irq_enable(); > > schedule(); > > + if (IS_ENABLED(CONFIG_MTD_XIP)) > > + local_irq_disable(); > > remove_wait_queue(&chip->wq, &wait); > > mutex_lock(&chip->mutex); > > continue; > > > Thanks, Miquèl