From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 801A43603F7 for ; Mon, 23 Mar 2026 21:23:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774301027; cv=none; b=JJJtPdRjYWjXy5XiJYPDhJnCRBEoOlFlj6KeQcI8urUwJI45z97gOdLJZUnD03mmzQcyceWOIxdYc9VI83zffEA0jQiqxHoLEpc/bqd+VzOdPPZHnrAjBvO1xoI8yHRTWfMC/uqfptdyfky5M0z3VfJqGI6pvgkHaNDyJvhTKc8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774301027; c=relaxed/simple; bh=8ov8jG8Q2BKX/gGixQkvTUqG8FPDZ0Y0JjSPvpemQe0=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=tr35XZuREx2oIauTJ/JtCPcFlJz1ATCBYgGqca6LmSXPmHLRAzZv4fakulqOsEl8shm3TgXmon/4DpBwipV3egGIR3USxlXlHc7iVveusfr296BegRgCpbrzt2PYXv5/8L1hRLqYw3iI1FcKGAfnGxOqK6i0OG/cb5T7N1ddjfg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Mg+H7au1; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Mg+H7au1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DB2A9C4CEF7; Mon, 23 Mar 2026 21:23:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1774301027; bh=8ov8jG8Q2BKX/gGixQkvTUqG8FPDZ0Y0JjSPvpemQe0=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=Mg+H7au1WJmufSPsBMqE9eKAW3+nKd4Sv0rGG0O6GyTLXSjEf1MkvCAwlv/7TmPeN 2EONc1H7pHnSmASmp3FL6n3h/zII5W0AMAMhFmDuhaH9z1KI+/UPS9ICcOEB9he8iI 21zGzuWtc67Y9eHw9z6yureFZi3uDzsapGuE3wqLX+P4Cl4fka9cs9XsVRjWI1A3RB jwYMvOJ9DzUx7g62wxrZmy1P2aAYuiJJwnCiiIxPUQNGUI62xD1PZkcM8eTswWczzl Tm/w6gF3jdXPx3Y9NRF7IR/60bwLSCT/1vOrFjtudZX2xIu/vd1BNxT17NU/+3WaKM 6vltCIUbCLXlQ== Date: Mon, 23 Mar 2026 14:23:40 -0700 From: Jakub Kicinski To: Adriano Vero Cc: michael.chan@broadcom.com, davem@davemloft.net, edumazet@google.com, pabeni@redhat.com, netdev@vger.kernel.org Subject: Re: [PATCH] net: broadcom: b44: Add missing dma_mapping_error in b44_start_xmit Message-ID: <20260323142340.13fded29@kernel.org> In-Reply-To: <20260323180913.188434-1-litaliano00.contact@gmail.com> References: <20260323180913.188434-1-litaliano00.contact@gmail.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Mon, 23 Mar 2026 19:09:13 +0100 Adriano Vero wrote: > The b44 driver calls dma_map_single() in the transmit path but fails to > check the return value for errors using dma_mapping_error(). You say it doesn't use dma_mapping_error() .. > If the DMA > mapping fails under memory pressure, it can lead to memory corruption. > > Add the missing check, drop the skb, and return NETDEV_TX_OK to prevent > ring corruption. > --- a/drivers/net/ethernet/broadcom/b44.c > +++ b/drivers/net/ethernet/broadcom/b44.c > @@ -964,8 +964,14 @@ static netdev_tx_t b44_start_xmit(struct sk_buff *skb, struct net_device *dev) > } > > mapping = dma_map_single(bp->sdev->dma_dev, skb->data, len, DMA_TO_DEVICE); > - if (dma_mapping_error(bp->sdev->dma_dev, mapping) || mapping + len > DMA_BIT_MASK(30)) { .. and yet this line clearly contains the check. Please explain what you mean and do not post a v2 until some reviewer requests that you do so. > - struct sk_buff *bounce_skb; > + > + if (dma_mapping_error(bp->sdev->dma_dev, mapping)) { > + dev_kfree_skb_any(skb); > + return NETDEV_TX_OK; > + } > + > + if (mapping + len > DMA_BIT_MASK(30)) { > + struct sk_buff *bounce_skb; > > /* Chip can't handle DMA to/from >1GB, use bounce buffer */ > if (!dma_mapping_error(bp->sdev->dma_dev, mapping))