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 81C8E1E25F8; Wed, 6 Nov 2024 12:42:48 +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=1730896968; cv=none; b=liUVOSAXL9cBupFKantEFa3oA8IhvsU0LvAUoJWxwkcsiEljxk2dIOAkI/UosKC/mepzw306ii93Ku7wdXSiLNLClbMzBJyJDEgIEcC6hOAVk8imTCcsCYrnVxVtVaQN1y1lW5abXwDLUtlszv3FZXPTAApBDA5XyXP1b3yTO0k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730896968; c=relaxed/simple; bh=HS6+UJ4aHwUjwZE9j/9tAMsV1BfBDJAbNnlSH/hvnng=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=BKcfJCtILicfG5pJ7CIvoyk1gTaTG8vmG66GYMa99JxFZilTuIO9jx6lBdWdIGsVSnt2gzHIoGV4FoOEXveVR2m/uSjvYxdoYlW4dhe6bhWhuC9jkcvsR8s/H+OuWdfz+atCRpmv4uYYrGbphmOKTypUwIufXAACLZGBR62OBbw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=st2LfaJ9; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="st2LfaJ9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0BEBDC4CED4; Wed, 6 Nov 2024 12:42:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1730896968; bh=HS6+UJ4aHwUjwZE9j/9tAMsV1BfBDJAbNnlSH/hvnng=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=st2LfaJ9/tIdOcnytRMVzujWf686uFFhehj3YHzNAU0NWCvYDqUWj2HJOakwoS21v NrAGM72qd6DvS5+SFK225qwleeoOtnfXAoMm1VhkGY5V9vPAU3KqFe7TqJDELiCnic MmuB/iru02ovjwA+Ek2x8NGtE7t3CrMpAU3NR/UQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Suraj Jaiswal , Furong Xu <0x1207@gmail.com>, Hariprasad Kelam , Simon Horman , Paolo Abeni , Sasha Levin Subject: [PATCH 6.1 022/126] net: stmmac: TSO: Fix unbalanced DMA map/unmap for non-paged SKB data Date: Wed, 6 Nov 2024 13:03:43 +0100 Message-ID: <20241106120306.695722994@linuxfoundation.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241106120306.038154857@linuxfoundation.org> References: <20241106120306.038154857@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Furong Xu <0x1207@gmail.com> [ Upstream commit 66600fac7a984dea4ae095411f644770b2561ede ] In case the non-paged data of a SKB carries protocol header and protocol payload to be transmitted on a certain platform that the DMA AXI address width is configured to 40-bit/48-bit, or the size of the non-paged data is bigger than TSO_MAX_BUFF_SIZE on a certain platform that the DMA AXI address width is configured to 32-bit, then this SKB requires at least two DMA transmit descriptors to serve it. For example, three descriptors are allocated to split one DMA buffer mapped from one piece of non-paged data: dma_desc[N + 0], dma_desc[N + 1], dma_desc[N + 2]. Then three elements of tx_q->tx_skbuff_dma[] will be allocated to hold extra information to be reused in stmmac_tx_clean(): tx_q->tx_skbuff_dma[N + 0], tx_q->tx_skbuff_dma[N + 1], tx_q->tx_skbuff_dma[N + 2]. Now we focus on tx_q->tx_skbuff_dma[entry].buf, which is the DMA buffer address returned by DMA mapping call. stmmac_tx_clean() will try to unmap the DMA buffer _ONLY_IF_ tx_q->tx_skbuff_dma[entry].buf is a valid buffer address. The expected behavior that saves DMA buffer address of this non-paged data to tx_q->tx_skbuff_dma[entry].buf is: tx_q->tx_skbuff_dma[N + 0].buf = NULL; tx_q->tx_skbuff_dma[N + 1].buf = NULL; tx_q->tx_skbuff_dma[N + 2].buf = dma_map_single(); Unfortunately, the current code misbehaves like this: tx_q->tx_skbuff_dma[N + 0].buf = dma_map_single(); tx_q->tx_skbuff_dma[N + 1].buf = NULL; tx_q->tx_skbuff_dma[N + 2].buf = NULL; On the stmmac_tx_clean() side, when dma_desc[N + 0] is closed by the DMA engine, tx_q->tx_skbuff_dma[N + 0].buf is a valid buffer address obviously, then the DMA buffer will be unmapped immediately. There may be a rare case that the DMA engine does not finish the pending dma_desc[N + 1], dma_desc[N + 2] yet. Now things will go horribly wrong, DMA is going to access a unmapped/unreferenced memory region, corrupted data will be transmited or iommu fault will be triggered :( In contrast, the for-loop that maps SKB fragments behaves perfectly as expected, and that is how the driver should do for both non-paged data and paged frags actually. This patch corrects DMA map/unmap sequences by fixing the array index for tx_q->tx_skbuff_dma[entry].buf when assigning DMA buffer address. Tested and verified on DWXGMAC CORE 3.20a Reported-by: Suraj Jaiswal Fixes: f748be531d70 ("stmmac: support new GMAC4") Signed-off-by: Furong Xu <0x1207@gmail.com> Reviewed-by: Hariprasad Kelam Reviewed-by: Simon Horman Link: https://patch.msgid.link/20241021061023.2162701-1-0x1207@gmail.com Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin --- .../net/ethernet/stmicro/stmmac/stmmac_main.c | 22 ++++++++++++++----- 1 file changed, 17 insertions(+), 5 deletions(-) diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c index 93630840309e7..045e57c444fd7 100644 --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c @@ -4183,11 +4183,6 @@ static netdev_tx_t stmmac_tso_xmit(struct sk_buff *skb, struct net_device *dev) if (dma_mapping_error(priv->device, des)) goto dma_map_err; - tx_q->tx_skbuff_dma[first_entry].buf = des; - tx_q->tx_skbuff_dma[first_entry].len = skb_headlen(skb); - tx_q->tx_skbuff_dma[first_entry].map_as_page = false; - tx_q->tx_skbuff_dma[first_entry].buf_type = STMMAC_TXBUF_T_SKB; - if (priv->dma_cap.addr64 <= 32) { first->des0 = cpu_to_le32(des); @@ -4206,6 +4201,23 @@ static netdev_tx_t stmmac_tso_xmit(struct sk_buff *skb, struct net_device *dev) stmmac_tso_allocator(priv, des, tmp_pay_len, (nfrags == 0), queue); + /* In case two or more DMA transmit descriptors are allocated for this + * non-paged SKB data, the DMA buffer address should be saved to + * tx_q->tx_skbuff_dma[].buf corresponding to the last descriptor, + * and leave the other tx_q->tx_skbuff_dma[].buf as NULL to guarantee + * that stmmac_tx_clean() does not unmap the entire DMA buffer too early + * since the tail areas of the DMA buffer can be accessed by DMA engine + * sooner or later. + * By saving the DMA buffer address to tx_q->tx_skbuff_dma[].buf + * corresponding to the last descriptor, stmmac_tx_clean() will unmap + * this DMA buffer right after the DMA engine completely finishes the + * full buffer transmission. + */ + tx_q->tx_skbuff_dma[tx_q->cur_tx].buf = des; + tx_q->tx_skbuff_dma[tx_q->cur_tx].len = skb_headlen(skb); + tx_q->tx_skbuff_dma[tx_q->cur_tx].map_as_page = false; + tx_q->tx_skbuff_dma[tx_q->cur_tx].buf_type = STMMAC_TXBUF_T_SKB; + /* Prepare fragments */ for (i = 0; i < nfrags; i++) { const skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; -- 2.43.0