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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C395CE95A94 for ; Sun, 8 Oct 2023 21:03:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229822AbjJHVD3 (ORCPT ); Sun, 8 Oct 2023 17:03:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51142 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229631AbjJHVD3 (ORCPT ); Sun, 8 Oct 2023 17:03:29 -0400 Received: from mail-pf1-x429.google.com (mail-pf1-x429.google.com [IPv6:2607:f8b0:4864:20::429]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 05EA6B6 for ; Sun, 8 Oct 2023 14:03:26 -0700 (PDT) Received: by mail-pf1-x429.google.com with SMTP id d2e1a72fcca58-692d2e8c003so3610681b3a.1 for ; Sun, 08 Oct 2023 14:03:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1696799005; x=1697403805; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=KRUv/QSnced096nWx46ar50Ge+209xa4Pte75ck/B5M=; b=PGsSrWpA+Q8LDgUPJueSS7HqZvqN8DBOn/f4CnZhK8yY8f/8HVCNvUfvao/NCHzdIA wTSUmiee/zicfbkXQTabt6xFmXlMBhftyPWxOW3jZsnHrrevZa2wu7VDICYN/hEq9xpK RgUGjlf/31Bw92oUxoOreAPIsozMlO1JaYg50= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1696799005; x=1697403805; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=KRUv/QSnced096nWx46ar50Ge+209xa4Pte75ck/B5M=; b=nMmI96AqyplPBIaeJRifwsPN3Vau9sJWAaSyGPKmv2by3AcKc6zC5oNRYDZtMZ3lgm bl7XWck90/WTFoaMkFmqjeVqKE+eCA5GwUHDvlAoDGApj2CIUs22/9EsXyKQ9ahDjvzd Y+94aZfQB07I6VSxAeileKdfL7/EVXLlkdk/1eBt6aEQ9XFNu5GCVce4ro2qKW6NtD/4 VRYK9a+wSo0r7lkoO946NiTIhutzhGhzMG8yyasj9LbeobJIzlQ6jDmmsqHFMLJAK6Co +w3+u7yfiYqnay0DyDE15xVDvU3g+eeShjEFLS40Ns55POZbyYcU9lOamysChjxsJyHe Wa7w== X-Gm-Message-State: AOJu0YwHWNZeQqdfbg7fVJNmQHLf1HMfsrZ9RwRQwpZVQ3deXM5/rfy0 /l5XPPP4XFbcwMxSRz8gX9Ma+A== X-Google-Smtp-Source: AGHT+IFQUzzmkCoYCWTxyoFQmDoMV6Gdvkd7UGx7JIod6TwuwuTa6MBHAwHgMCrHziMMoNMDAaAD3A== X-Received: by 2002:a17:902:ec90:b0:1c7:27a1:a9e5 with SMTP id x16-20020a170902ec9000b001c727a1a9e5mr17488409plg.33.1696799005512; Sun, 08 Oct 2023 14:03:25 -0700 (PDT) Received: from www.outflux.net (198-0-35-241-static.hfc.comcastbusiness.net. [198.0.35.241]) by smtp.gmail.com with ESMTPSA id g6-20020a170902740600b001bc18e579aesm7868134pll.101.2023.10.08.14.03.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 08 Oct 2023 14:03:24 -0700 (PDT) Date: Sun, 8 Oct 2023 14:03:23 -0700 From: Kees Cook To: Christophe JAILLET Cc: gustavoars@kernel.org, Daniel Mack , Haojian Zhuang , Robert Jarzmik , Vinod Koul , linux-hardening@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org, linux-arm-kernel@lists.infradead.org, dmaengine@vger.kernel.org Subject: Re: [PATCH 1/2] dmaengine: pxa_dma: Remove an erroneous BUG_ON() in pxad_free_desc() Message-ID: <202310081402.A9A8C49@keescook> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org On Sat, Oct 07, 2023 at 01:13:09PM +0200, Christophe JAILLET wrote: > If pxad_alloc_desc() fails on the first dma_pool_alloc() call, then > sw_desc->nb_desc is zero. > In such a case pxad_free_desc() is called and it will BUG_ON(). > > Remove this erroneous BUG_ON(). Perhaps it could be changed to a WARN_ON()? > It is also useless, because if "sw_desc->nb_desc == 0", then, on the first > iteration of the for loop, i is -1 and the loop will not be executed. > (both i and sw_desc->nb_desc are 'int') Agreed. > > Fixes: a57e16cf0333 ("dmaengine: pxa: add pxa dmaengine driver") > Signed-off-by: Christophe JAILLET > --- > drivers/dma/pxa_dma.c | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/drivers/dma/pxa_dma.c b/drivers/dma/pxa_dma.c > index 3c574dc0613b..94cef2905940 100644 > --- a/drivers/dma/pxa_dma.c > +++ b/drivers/dma/pxa_dma.c > @@ -722,7 +722,6 @@ static void pxad_free_desc(struct virt_dma_desc *vd) > dma_addr_t dma; > struct pxad_desc_sw *sw_desc = to_pxad_sw_desc(vd); > > - BUG_ON(sw_desc->nb_desc == 0); > for (i = sw_desc->nb_desc - 1; i >= 0; i--) { > if (i > 0) > dma = sw_desc->hw_desc[i - 1]->ddadr; > -- > 2.34.1 > -- Kees Cook