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=-11.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 469B8C433DF for ; Tue, 11 Aug 2020 16:03:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 14E2520774 for ; Tue, 11 Aug 2020 16:03:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729039AbgHKQDt (ORCPT ); Tue, 11 Aug 2020 12:03:49 -0400 Received: from netrider.rowland.org ([192.131.102.5]:37653 "HELO netrider.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1728797AbgHKQDt (ORCPT ); Tue, 11 Aug 2020 12:03:49 -0400 Received: (qmail 337967 invoked by uid 1000); 11 Aug 2020 12:03:48 -0400 Date: Tue, 11 Aug 2020 12:03:48 -0400 From: Alan Stern To: trix@redhat.com Cc: gregkh@linuxfoundation.org, acozzette@cs.hmc.edu, linux-usb@vger.kernel.org, usb-storage@lists.one-eyed-alien.net, linux-kernel@vger.kernel.org Subject: Re: [PATCH] USB: realtek_cr: fix return check for dma functions Message-ID: <20200811160348.GD335280@rowland.harvard.edu> References: <20200811151505.12222-1-trix@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200811151505.12222-1-trix@redhat.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Aug 11, 2020 at 08:15:05AM -0700, trix@redhat.com wrote: > From: Tom Rix > > clang static analysis reports this representative problem > > realtek_cr.c:639:3: warning: The left expression of the compound > assignment is an uninitialized value. The computed value will > also be garbage > SET_BIT(value, 2); > ^~~~~~~~~~~~~~~~~ > > value is set by a successful call to rts51x_read_mem() > > retval = rts51x_read_mem(us, 0xFE77, &value, 1); > if (retval < 0) > return -EIO; > > A successful call to rts51x_read_mem returns 0, failure can > return positive and negative values. This check is wrong > for a number of functions. Fix the retval check. > > Fixes: 065e60964e29 ("ums_realtek: do not use stack memory for DMA") > Signed-off-by: Tom Rix > --- > drivers/usb/storage/realtek_cr.c | 36 ++++++++++++++++---------------- > 1 file changed, 18 insertions(+), 18 deletions(-) > > diff --git a/drivers/usb/storage/realtek_cr.c b/drivers/usb/storage/realtek_cr.c > index 3789698d9d3c..b983753e2368 100644 > --- a/drivers/usb/storage/realtek_cr.c > +++ b/drivers/usb/storage/realtek_cr.c > @@ -481,16 +481,16 @@ static int enable_oscillator(struct us_data *us) > u8 value; > > retval = rts51x_read_mem(us, 0xFE77, &value, 1); > - if (retval < 0) > + if (retval != STATUS_SUCCESS) > return -EIO; Instead of changing all these call sites, wouldn't it be a lot easier just to change rts51x_read_mem() to make it always return a negative value (such as -EIO) when there's an error? Alan Stern