From patchwork Wed Aug 12 13:20:30 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oliver Neukum X-Patchwork-Id: 11710811 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id ADD5E138C for ; Wed, 12 Aug 2020 13:20:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A04CD207F7 for ; Wed, 12 Aug 2020 13:20:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727977AbgHLNUs (ORCPT ); Wed, 12 Aug 2020 09:20:48 -0400 Received: from mx2.suse.de ([195.135.220.15]:55690 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727788AbgHLNUs (ORCPT ); Wed, 12 Aug 2020 09:20:48 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 8B7A8B764; Wed, 12 Aug 2020 13:21:08 +0000 (UTC) From: Oliver Neukum To: penguin-kernel@i-love.sakura.ne.jp, bjorn@mork.no, linux-usb@vger.kernel.org Cc: Oliver Neukum Subject: [RFC 1/5] CDC-WDM: fix hangs in flush() Date: Wed, 12 Aug 2020 15:20:30 +0200 Message-Id: <20200812132034.14363-2-oneukum@suse.com> X-Mailer: git-send-email 2.16.4 In-Reply-To: <20200812132034.14363-1-oneukum@suse.com> References: <20200812132034.14363-1-oneukum@suse.com> Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org In a multithreaded scenario a flush() and a write() may be waiting for the same IO to complete. Hence completion of output must use wake_up_all(), even in error handling, while a flush may be waiting for an intended but not started Io. Reported-by: Tetsuo Handa Signed-off-by: Oliver Neukum --- drivers/usb/class/cdc-wdm.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc-wdm.c index 7f5de956a2fc..a834294ce4e5 100644 --- a/drivers/usb/class/cdc-wdm.c +++ b/drivers/usb/class/cdc-wdm.c @@ -151,7 +151,7 @@ static void wdm_out_callback(struct urb *urb) kfree(desc->outbuf); desc->outbuf = NULL; clear_bit(WDM_IN_USE, &desc->flags); - wake_up(&desc->wait); + wake_up_all(&desc->wait); } static void wdm_in_callback(struct urb *urb) @@ -424,6 +424,7 @@ static ssize_t wdm_write if (rv < 0) { desc->outbuf = NULL; clear_bit(WDM_IN_USE, &desc->flags); + wake_up_all(&desc->wait); /* for flush() */ dev_err(&desc->intf->dev, "Tx URB error: %d\n", rv); rv = usb_translate_errors(rv); goto out_free_mem_pm; @@ -586,6 +587,7 @@ static ssize_t wdm_read static int wdm_flush(struct file *file, fl_owner_t id) { struct wdm_device *desc = file->private_data; + int rv; wait_event(desc->wait, /* @@ -600,11 +602,12 @@ static int wdm_flush(struct file *file, fl_owner_t id) /* cannot dereference desc->intf if WDM_DISCONNECTING */ if (test_bit(WDM_DISCONNECTING, &desc->flags)) return -ENODEV; - if (desc->werr < 0) + rv = desc->werr; + if (rv < 0) dev_err(&desc->intf->dev, "Error in flush path: %d\n", - desc->werr); + rv); - return usb_translate_errors(desc->werr); + return usb_translate_errors(rv); } static __poll_t wdm_poll(struct file *file, struct poll_table_struct *wait) From patchwork Wed Aug 12 13:20:31 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oliver Neukum X-Patchwork-Id: 11710813 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 053B51392 for ; Wed, 12 Aug 2020 13:20:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E16FD207DA for ; Wed, 12 Aug 2020 13:20:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728012AbgHLNUu (ORCPT ); Wed, 12 Aug 2020 09:20:50 -0400 Received: from mx2.suse.de ([195.135.220.15]:55714 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727817AbgHLNUs (ORCPT ); Wed, 12 Aug 2020 09:20:48 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 02DCEB76B; Wed, 12 Aug 2020 13:21:09 +0000 (UTC) From: Oliver Neukum To: penguin-kernel@i-love.sakura.ne.jp, bjorn@mork.no, linux-usb@vger.kernel.org Cc: Oliver Neukum Subject: [RFC 2/5] CDC-WDM: introduce a timeout in flush() Date: Wed, 12 Aug 2020 15:20:31 +0200 Message-Id: <20200812132034.14363-3-oneukum@suse.com> X-Mailer: git-send-email 2.16.4 In-Reply-To: <20200812132034.14363-1-oneukum@suse.com> References: <20200812132034.14363-1-oneukum@suse.com> Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org Malicious or defective hardware may cease communication while flush() is running. In last consequence we need a timeout, as hardware that remains silent must be ignored. The 30 seconds are coming out of thin air. Reported-by: Tetsuo Handa Signed-off-by: Oliver Neukum --- drivers/usb/class/cdc-wdm.c | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc-wdm.c index a834294ce4e5..329f8d5f7c8d 100644 --- a/drivers/usb/class/cdc-wdm.c +++ b/drivers/usb/class/cdc-wdm.c @@ -58,6 +58,9 @@ MODULE_DEVICE_TABLE (usb, wdm_ids); #define WDM_MAX 16 +/* flush() is uninterruptible, but we cannot wait forever */ +#define WDM_FLUSH_TIMEOUT (30 * HZ) + /* CDC-WMC r1.1 requires wMaxCommand to be "at least 256 decimal (0x100)" */ #define WDM_DEFAULT_BUFSIZE 256 @@ -589,7 +592,7 @@ static int wdm_flush(struct file *file, fl_owner_t id) struct wdm_device *desc = file->private_data; int rv; - wait_event(desc->wait, + rv = wait_event_timeout(desc->wait, /* * needs both flags. We cannot do with one * because resetting it would cause a race @@ -597,11 +600,14 @@ static int wdm_flush(struct file *file, fl_owner_t id) * a disconnect */ !test_bit(WDM_IN_USE, &desc->flags) || - test_bit(WDM_DISCONNECTING, &desc->flags)); + test_bit(WDM_DISCONNECTING, &desc->flags), + WDM_FLUSH_TIMEOUT); /* cannot dereference desc->intf if WDM_DISCONNECTING */ if (test_bit(WDM_DISCONNECTING, &desc->flags)) return -ENODEV; + if (!rv) + return -EIO; rv = desc->werr; if (rv < 0) dev_err(&desc->intf->dev, "Error in flush path: %d\n", @@ -659,6 +665,14 @@ static int wdm_open(struct inode *inode, struct file *file) goto out; } + /* + * in case flush() had timed out + */ + usb_kill_urb(desc->command); + spin_lock_irq(&desc->iuspin); + desc->werr = 0; + spin_unlock_irq(&desc->iuspin); + /* using write lock to protect desc->count */ mutex_lock(&desc->wlock); if (!desc->count++) { From patchwork Wed Aug 12 13:20:32 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oliver Neukum X-Patchwork-Id: 11710815 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 75AE21744 for ; Wed, 12 Aug 2020 13:20:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6744C206DA for ; Wed, 12 Aug 2020 13:20:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728016AbgHLNUx (ORCPT ); Wed, 12 Aug 2020 09:20:53 -0400 Received: from mx2.suse.de ([195.135.220.15]:55736 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727854AbgHLNUs (ORCPT ); Wed, 12 Aug 2020 09:20:48 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 6D2A1B76D; Wed, 12 Aug 2020 13:21:09 +0000 (UTC) From: Oliver Neukum To: penguin-kernel@i-love.sakura.ne.jp, bjorn@mork.no, linux-usb@vger.kernel.org Cc: Oliver Neukum Subject: [RFC 3/5] CDC-WDM: making flush() interruptible Date: Wed, 12 Aug 2020 15:20:32 +0200 Message-Id: <20200812132034.14363-4-oneukum@suse.com> X-Mailer: git-send-email 2.16.4 In-Reply-To: <20200812132034.14363-1-oneukum@suse.com> References: <20200812132034.14363-1-oneukum@suse.com> Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org There is no need for flush() to be uninterruptible. close(2) is allowed to return -EAGAIN. Change it. Reported-by: Tetsuo Handa Signed-off-by: Oliver Neukum --- drivers/usb/class/cdc-wdm.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc-wdm.c index 329f8d5f7c8d..f442f34f38da 100644 --- a/drivers/usb/class/cdc-wdm.c +++ b/drivers/usb/class/cdc-wdm.c @@ -592,7 +592,7 @@ static int wdm_flush(struct file *file, fl_owner_t id) struct wdm_device *desc = file->private_data; int rv; - rv = wait_event_timeout(desc->wait, + rv = wait_event_interruptible_timeout(desc->wait, /* * needs both flags. We cannot do with one * because resetting it would cause a race @@ -608,6 +608,8 @@ static int wdm_flush(struct file *file, fl_owner_t id) return -ENODEV; if (!rv) return -EIO; + if (rv < 0) + return -EINTR; rv = desc->werr; if (rv < 0) dev_err(&desc->intf->dev, "Error in flush path: %d\n", From patchwork Wed Aug 12 13:20:33 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oliver Neukum X-Patchwork-Id: 11710819 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 5F6681744 for ; Wed, 12 Aug 2020 13:20:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5174C207F7 for ; Wed, 12 Aug 2020 13:20:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728021AbgHLNUy (ORCPT ); Wed, 12 Aug 2020 09:20:54 -0400 Received: from mx2.suse.de ([195.135.220.15]:55752 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727961AbgHLNUt (ORCPT ); Wed, 12 Aug 2020 09:20:49 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id DF7BEB76A; Wed, 12 Aug 2020 13:21:09 +0000 (UTC) From: Oliver Neukum To: penguin-kernel@i-love.sakura.ne.jp, bjorn@mork.no, linux-usb@vger.kernel.org Cc: Oliver Neukum Subject: [RFC 4/5] CDC-WDM: fix race reporting errors in flush Date: Wed, 12 Aug 2020 15:20:33 +0200 Message-Id: <20200812132034.14363-5-oneukum@suse.com> X-Mailer: git-send-email 2.16.4 In-Reply-To: <20200812132034.14363-1-oneukum@suse.com> References: <20200812132034.14363-1-oneukum@suse.com> Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org In case a race was lost and multiple fds used, an error could be reported multiple times. To fix this a spinlock must be taken. Signed-off-by: Oliver Neukum --- drivers/usb/class/cdc-wdm.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc-wdm.c index f442f34f38da..6071c9044574 100644 --- a/drivers/usb/class/cdc-wdm.c +++ b/drivers/usb/class/cdc-wdm.c @@ -610,10 +610,14 @@ static int wdm_flush(struct file *file, fl_owner_t id) return -EIO; if (rv < 0) return -EINTR; + + spin_lock_irq(&desc->iuspin); rv = desc->werr; + desc->werr = 0; + spin_unlock_irq(&desc->iuspin); + if (rv < 0) - dev_err(&desc->intf->dev, "Error in flush path: %d\n", - rv); + dev_err(&desc->intf->dev, "Error in flush path: %d\n", rv); return usb_translate_errors(rv); } From patchwork Wed Aug 12 13:20:34 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oliver Neukum X-Patchwork-Id: 11710817 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 06D1E138C for ; Wed, 12 Aug 2020 13:20:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ED2D42080C for ; Wed, 12 Aug 2020 13:20:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728018AbgHLNUy (ORCPT ); Wed, 12 Aug 2020 09:20:54 -0400 Received: from mx2.suse.de ([195.135.220.15]:55768 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728004AbgHLNUt (ORCPT ); Wed, 12 Aug 2020 09:20:49 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 5960CB76F; Wed, 12 Aug 2020 13:21:10 +0000 (UTC) From: Oliver Neukum To: penguin-kernel@i-love.sakura.ne.jp, bjorn@mork.no, linux-usb@vger.kernel.org Cc: Oliver Neukum Subject: [RFC 5/5] CDC-WDM: remove use of intf->dev after potential disconnect Date: Wed, 12 Aug 2020 15:20:34 +0200 Message-Id: <20200812132034.14363-6-oneukum@suse.com> X-Mailer: git-send-email 2.16.4 In-Reply-To: <20200812132034.14363-1-oneukum@suse.com> References: <20200812132034.14363-1-oneukum@suse.com> Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org After a disconnect intf->dev is not a valid pointer any longer as flush() uses it only for logging purposes logging is not worth it. Remove the dev_err() Reported-by: Tetsuo Handa Signed-off-by: Oliver Neukum --- drivers/usb/class/cdc-wdm.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc-wdm.c index 6071c9044574..2dcf1fb16f2b 100644 --- a/drivers/usb/class/cdc-wdm.c +++ b/drivers/usb/class/cdc-wdm.c @@ -616,9 +616,6 @@ static int wdm_flush(struct file *file, fl_owner_t id) desc->werr = 0; spin_unlock_irq(&desc->iuspin); - if (rv < 0) - dev_err(&desc->intf->dev, "Error in flush path: %d\n", rv); - return usb_translate_errors(rv); }