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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id DFF4CE95A67 for ; Sun, 8 Oct 2023 21:04:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=mLkAxGYeSL6XcgYFYSY3e6wo8NGIMt3GEqZ4vwFtcQQ=; b=zdAZc8V+vE5xwb 7i0FqaLYyEtPpl7cSaDRmrvgDuYXz1uIrUdNmBYt9XN+kuvVJXM6K/LJu8iKNUXXnYGDBqGR9oduZ ct2041tln0UBzZej4Earyhw3kMoo7zS6c1kqBVzUZhZIfMRfzRjgEm1JtsRfn+BHH4ZENPW81kb5V plfTOCeu3GU8v6wv7it83iYjmeSI+15cBCr1VMacQoEINyacpFsODzLhsNlW4LQUsn5EyQMfThrf8 mAS5AzVnEJYcWhXYW2H7Q6qIg9MezfvhgIgahFrVWmDKCl1qTLt1lSoRgtQxgzp3ZzzkY9QIQAHTy iCMTVRBFvH2rhdm8MMlA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qpavy-009JYN-1b; Sun, 08 Oct 2023 21:03:30 +0000 Received: from mail-pl1-x62b.google.com ([2607:f8b0:4864:20::62b]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qpavv-009JXM-1e for linux-arm-kernel@lists.infradead.org; Sun, 08 Oct 2023 21:03:28 +0000 Received: by mail-pl1-x62b.google.com with SMTP id d9443c01a7336-1c63164a2b6so36349245ad.0 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=lists.infradead.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=Fid2FIkH/kiaJo3pplTNeYGPhOx9bj7ql98wo2E+ekZKTRLqHMx00PV55vfpEI/wV7 yL5ETi2yrv2g6gSET2+u5xpclNqXas0TsQcLi/sTdBD3oZ/X/lRu6LT10Huvz7ZDQPwN lcuHL1izeHsqnKlVK+IkUBaW1AUIfAhtmCu7I= 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=FtNuP6TRD1n6twl5EvN+8LEUFtmLxqrWKNalvN+H23Zxr5AQNze2VDnYRD0pqEqNFk VQoRqlZ0dDsEJy3fAf6oMw2ypP+kw1+zqNwYWrqPlqaA+xcKsxu54b7UsRz8ZQbrWuj0 twzQLK4zHEJkYbPOkYbGRxF6yEADWyyKP4JRdpvR2UCkeUcnahvJvW6Jtj4iZHQlPcLz f7VWqcPHzLht3NHnJuxrp6gucU3kzvT+/4wwm9YUQ/I2wRAXvcelhfogORCel7EmgMAP Ao0WHEKfNXne0H+sHpNNQET5aPaF9Q9nVt9E7iDCnliAyY4in5aomM1UKIa/JsWdww85 6HMw== X-Gm-Message-State: AOJu0YzFb3n4pu8Qw9nDuGKwcQW7dYrQxSpL3GYlYLI0bQR8YT6YNTcm XUiMOa8hqYS6Vok7WrpSHTHihyN+dzRh5Gm4jd8= 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-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20231008_140327_553079_B58578FF X-CRM114-Status: GOOD ( 21.85 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.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 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel