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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 97C14C433E0 for ; Thu, 21 Jan 2021 09:52:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4C3C12399A for ; Thu, 21 Jan 2021 09:52:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728469AbhAUJwJ (ORCPT ); Thu, 21 Jan 2021 04:52:09 -0500 Received: from mail.kernel.org ([198.145.29.99]:46926 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726668AbhAUJuk (ORCPT ); Thu, 21 Jan 2021 04:50:40 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 466EA235DD; Thu, 21 Jan 2021 09:49:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1611222598; bh=ulf91MyYl8gM/X8Gf09neoMWDbaSWdDBAR1ssPtAdpg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=B9mT+4VKAdzjcHnCkM7WfeqOhAPOQYjXQbU6zpxbvLLyI544o45J7BcMLPSVd+ukc bbYeRvZ/2OrqsutS871mlD84ypLyHW/HcQfPF892qpVzSTn+TIdNbh5tc3rI/gmR+f DHuO3RIyJLecn5u0egNDXwQKrVxbNzwyRQ6MfBP0= Date: Thu, 21 Jan 2021 10:49:56 +0100 From: Greg KH To: Dongliang Mu Cc: davem@davemloft.net, helmut.schaa@googlemail.com, kvalo@codeaurora.org, linux-kernel@vger.kernel.org, linux-wireless@vger.kernel.org, netdev@vger.kernel.org, sgruszka@redhat.com Subject: Re: [PATCH] rt2x00: reset reg earlier in rt2500usb_register_read Message-ID: References: <20210121092026.3261412-1-mudongliangabcd@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210121092026.3261412-1-mudongliangabcd@gmail.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 21, 2021 at 05:20:26PM +0800, Dongliang Mu wrote: > In the function rt2500usb_register_read(_lock), reg is uninitialized > in some situation. Then KMSAN reports uninit-value at its first memory > access. To fix this issue, add one reg initialization in the function > rt2500usb_register_read and rt2500usb_register_read_lock > > BUG: KMSAN: uninit-value in rt2500usb_init_eeprom rt2500usb.c:1443 [inline] > BUG: KMSAN: uninit-value in rt2500usb_probe_hw+0xb5e/0x22a0 rt2500usb.c:1757 > CPU: 0 PID: 3369 Comm: kworker/0:2 Not tainted 5.3.0-rc7+ #0 > Hardware name: Google Compute Engine > Workqueue: usb_hub_wq hub_event > Call Trace: > __dump_stack lib/dump_stack.c:77 [inline] > dump_stack+0x191/0x1f0 lib/dump_stack.c:113 > kmsan_report+0x162/0x2d0 mm/kmsan/kmsan_report.c:109 > __msan_warning+0x75/0xe0 mm/kmsan/kmsan_instr.c:294 > rt2500usb_init_eeprom wireless/ralink/rt2x00/rt2500usb.c:1443 [inline] > rt2500usb_probe_hw+0xb5e/0x22a0 wireless/ralink/rt2x00/rt2500usb.c:1757 > rt2x00lib_probe_dev+0xba9/0x3260 wireless/ralink/rt2x00/rt2x00dev.c:1427 > rt2x00usb_probe+0x7ae/0xf60 wireless/ralink/rt2x00/rt2x00usb.c:842 > rt2500usb_probe+0x50/0x60 wireless/ralink/rt2x00/rt2500usb.c:1966 > ...... > > Local variable description: ----reg.i.i@rt2500usb_probe_hw > Variable was created at: > rt2500usb_register_read wireless/ralink/rt2x00/rt2500usb.c:51 [inline] > rt2500usb_init_eeprom wireless/ralink/rt2x00/rt2500usb.c:1440 [inline] > rt2500usb_probe_hw+0x774/0x22a0 wireless/ralink/rt2x00/rt2500usb.c:1757 > rt2x00lib_probe_dev+0xba9/0x3260 wireless/ralink/rt2x00/rt2x00dev.c:1427 > > Signed-off-by: Dongliang Mu > --- > drivers/net/wireless/ralink/rt2x00/rt2500usb.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/net/wireless/ralink/rt2x00/rt2500usb.c b/drivers/net/wireless/ralink/rt2x00/rt2500usb.c > index fce05fc88aaf..f6c93a25b18c 100644 > --- a/drivers/net/wireless/ralink/rt2x00/rt2500usb.c > +++ b/drivers/net/wireless/ralink/rt2x00/rt2500usb.c > @@ -48,6 +48,7 @@ static u16 rt2500usb_register_read(struct rt2x00_dev *rt2x00dev, > const unsigned int offset) > { > __le16 reg; > + memset(®, 0, sizeof(reg)); As was pointed out, just set reg = 0 on the line above please. > rt2x00usb_vendor_request_buff(rt2x00dev, USB_MULTI_READ, > USB_VENDOR_REQUEST_IN, offset, > ®, sizeof(reg)); Are you sure this is valid to call this function with a variable on the stack like this? How did you test this change? thanks, greg k-h