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[59.127.145.64]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2d0aa4c94d4sm33717415ad.65.2026.08.06.08.54.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 06 Aug 2026 08:54:49 -0700 (PDT) From: Zhi-Jun You To: pabeni@redhat.com Cc: andrew+netdev@lunn.ch, angelogioacchino.delregno@collabora.com, davem@davemloft.net, edumazet@google.com, hujy652@gmail.com, kuba@kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mediatek@lists.infradead.org, lorenzo@kernel.org, matthias.bgg@gmail.com, nbd@nbd.name, netdev@vger.kernel.org, sujuan.chen@mediatek.com Subject: Re: [PATCH net v3 2/2] net:ethernet: mtk_wed: setup WDMA_RING_TX(0) for non-DBDC MT7986 Date: Thu, 6 Aug 2026 23:54:30 +0800 Message-ID: <20260806155430.768-1-hujy652@gmail.com> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260730090030.201100-1-pabeni@redhat.com> References: <20260724172040.1653-2-hujy652@gmail.com> <20260730090030.201100-1-pabeni@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Mutt-References: <20260730090030.201100-1-pabeni@redhat.com> X-Mutt-Fcc: ~/sent Content-Transfer-Encoding: 8bit On Thu, Jul 30, 2026 at 11:00:30AM +0200, Paolo Abeni wrote: > From: AI Reviewer > > This is an AI-generated review of your patch. The human sending this > email has considered the AI review valid, or at least plausible. > Full review at: https://sashiko.dev/ > --- > --- Patch [2]: [PATCH net v3 2/2] net:ethernet: mtk_wed: setup WDMA_RING_TX(0) for non-DBDC MT7986 --- > commit 30cd2d1bc8bf876e5d201d631684431920a3f165 > Author: Zhi-Jun You > > net:ethernet: mtk_wed: setup WDMA_RING_TX(0) for non-DBDC MT7986 > > This commit fixes an issue on non-DBDC MT7986 where WDMA_RING_TX(0) is > never set up because idx is 1, even though it is required for WED RX to > function. It addresses this by explicitly calling mtk_wed_wdma_tx_ring_setup > if the WED version is v2 and rx_ring[0] is unallocated. > > Link: https://lore.kernel.org/r/20260711112128.971-1-hujy652@gmail.com > Link: https://lore.kernel.org/r/20260630144831.1109-1-hujy652@gmail.com > > > diff --git a/drivers/net/ethernet/mediatek/mtk_wed.c b/drivers/net/ethernet/mediatek/mtk_wed.c > > --- a/drivers/net/ethernet/mediatek/mtk_wed.c > > +++ b/drivers/net/ethernet/mediatek/mtk_wed.c > [ ... ] > > @@ -2334,6 +2334,13 @@ mtk_wed_start(struct mtk_wed_device *dev, u32 irq_mask) > > if (!dev->rx_wdma[i].desc) > > mtk_wed_wdma_rx_ring_setup(dev, i, 16, false); > > [Severity: High] > This is a pre-existing issue, but does this code ignore the return value > from mtk_wed_wdma_rx_ring_setup()? > > If mtk_wed_ring_alloc() fails due to memory pressure, it returns an error > without configuring the hardware base registers. Because the error is > ignored, when DMA is later enabled in mtk_wed_start(), could the hardware > attempt to fetch from unmapped physical addresses and cause an IOMMU fault? > > > > > + /* > > + * non-DBDC MT7986 allocates only rx_ring[1] and tx_wdma[1] during setup > > + * but tx_wdma[0] is also needed for WED to function. > > + */ > > + if (mtk_wed_is_v2(dev->hw) && !dev->rx_ring[0].desc) > > + mtk_wed_wdma_tx_ring_setup(dev, 0, MTK_WED_WDMA_RING_SIZE, !!dev->tx_wdma[0].desc); > > [Severity: High] > Does this new call to mtk_wed_wdma_tx_ring_setup() also need to check its > return value? > > Similar to the RX ring above, if mtk_wed_ring_alloc() fails to allocate > memory, the hardware base registers won't be configured. Since the caller > proceeds to enable hardware DMA regardless, might this lead to the WED > processing descriptors from unmapped memory and causing memory corruption > or a system crash? > I am not sure how to proceed with this. Can Felix or Lorenzo comment this? Best regards, Zhi-Jun > > + > > if (dev->wlan.hw_rro) { > > for (i = 0; i < MTK_WED_RX_PAGE_QUEUES; i++) { > -- > This is an AI-generated review. >