From patchwork Sun Aug 30 18:36:46 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tom Rix X-Patchwork-Id: 297806 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=-13.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT 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 3AA09C433E6 for ; Sun, 30 Aug 2020 18:37:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0D8932071B for ; Sun, 30 Aug 2020 18:36:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="XXe8ONkA" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726492AbgH3Sg6 (ORCPT ); Sun, 30 Aug 2020 14:36:58 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:22554 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726380AbgH3Sg5 (ORCPT ); Sun, 30 Aug 2020 14:36:57 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1598812616; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc; bh=QozYeGLLb3VY909mnDA2JjEU+D2LsIUp8jIV0Jpgmp4=; b=XXe8ONkAOIOg48XgLbK5kVSJL4L1HGy63VAqzpewlKUEeZZcOl8S7OKa+XgxzXuI/It+Ta oeNNkJ2d+yd+RKfS2cFbIy4P0RsI08MVsHlXS0eoqiByT9dLC4S+nV0eCdaPy4B1n/uUEH YDS2G2RzR17t8uwpM8qyYc1TVbFmxPY= Received: from mail-il1-f200.google.com (mail-il1-f200.google.com [209.85.166.200]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-75-O4ts9YZTMNSUzV5MyeqLjQ-1; Sun, 30 Aug 2020 14:36:53 -0400 X-MC-Unique: O4ts9YZTMNSUzV5MyeqLjQ-1 Received: by mail-il1-f200.google.com with SMTP id 2so3555975ill.10 for ; Sun, 30 Aug 2020 11:36:53 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=QozYeGLLb3VY909mnDA2JjEU+D2LsIUp8jIV0Jpgmp4=; b=k0+r08kUSoC4tFJ2j5V34CJSSm+0CvpfQXGKvfiz6RjDrhNc4hEURMhK6MLOSeXDGM 0lZk8Qcz8FI/5xRwFDQhPhQoAhA+9c7sGqLRujpdy9Kz3BQd2jo2wh6UN4QPl0XtIJc7 ZKZY1iQzzqrbZNEnX58RbJuD1p1umU7e4BRhP+UAVj0pHREnoLfXlOdrMKU7lNLW5Uat qSZ9Djh5ldqzaKwXNaYQbLwMBjC282wPAbeKRO9NiDc0YZwe1egL81lZ6ctJOogXdaBg vDVn+sttSWKBwxhL8PdqzuKvMF1Jgx5VQTC5ErhKCVXx9Qsq7kGe08s7FIUZf+lwvURI Qcjg== X-Gm-Message-State: AOAM532vZ70n0E4Jt0c/9jb1ylw3EZECgm54VDvkrGneFgze5IV/MuS1 kNRJGE11O7xOm0zeu5QMaYzHp9rnWxivPCjEelzFksRuCw+w1r/LMJdw0WfGxaLmMaH3lAnf/BY VrNwi0SHeXWYA944Lz/hG X-Received: by 2002:a92:c904:: with SMTP id t4mr6323572ilp.257.1598812612571; Sun, 30 Aug 2020 11:36:52 -0700 (PDT) X-Google-Smtp-Source: ABdhPJws0aS2JRLx2nRnOEJQonJ8J7aNV73fnvMcA6Cq8vQw0/+MPUr+w4mfxekC3wDSgZkuIXIHRg== X-Received: by 2002:a92:c904:: with SMTP id t4mr6323556ilp.257.1598812612345; Sun, 30 Aug 2020 11:36:52 -0700 (PDT) Received: from trix.remote.csb (075-142-250-213.res.spectrum.com. [75.142.250.213]) by smtp.gmail.com with ESMTPSA id x185sm2883927iof.41.2020.08.30.11.36.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 30 Aug 2020 11:36:51 -0700 (PDT) From: trix@redhat.com To: balbi@kernel.org, gregkh@linuxfoundation.org, natechancellor@gmail.com, ndesaulniers@google.com, christophe.jaillet@wanadoo.fr, peter.chen@nxp.com, b-liu@ti.com, chunfeng.yun@mediatek.com, novikov@ispras.ru, yanaijie@huawei.com Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Tom Rix Subject: [PATCH] usb: gadget: net2272: assert for a valid dma request Date: Sun, 30 Aug 2020 11:36:46 -0700 Message-Id: <20200830183646.24930-1-trix@redhat.com> X-Mailer: git-send-email 2.18.1 Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org From: Tom Rix clang static analysis flags this representive problem net2272.c:1541:8: warning: Dereference of null pointer if ((req->req.length % ep->ep.maxpacket != 0) || ^~~~~~~~~~~~~~~ This is mostly not a problem. In net2272_handle_dma(), even though every path through the routine dereferences req, it is set to NULL when the ep->queue is empty. If the eq->queue was ever empty this would have oops. So the else statement should not be needed. If it is, flag it as a BUG. Signed-off-by: Tom Rix --- drivers/usb/gadget/udc/net2272.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/drivers/usb/gadget/udc/net2272.c b/drivers/usb/gadget/udc/net2272.c index 44d1ea2307bb..8301723a8b1a 100644 --- a/drivers/usb/gadget/udc/net2272.c +++ b/drivers/usb/gadget/udc/net2272.c @@ -1506,17 +1506,16 @@ static int net2272_stop(struct usb_gadget *_gadget) static void net2272_handle_dma(struct net2272_ep *ep) { - struct net2272_request *req; + struct net2272_request *req = NULL; unsigned len; int status; if (!list_empty(&ep->queue)) req = list_entry(ep->queue.next, struct net2272_request, queue); - else - req = NULL; dev_vdbg(ep->dev->dev, "handle_dma %s req %p\n", ep->ep.name, req); + BUG_ON(!req); /* Ensure DREQ is de-asserted */ net2272_write(ep->dev, DMAREQ,