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); }