From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752428AbdKVX31 (ORCPT ); Wed, 22 Nov 2017 18:29:27 -0500 Received: from omzsmtpe02.verizonbusiness.com ([199.249.25.209]:52926 "EHLO omzsmtpe02.verizonbusiness.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751742AbdKVWYI (ORCPT ); Wed, 22 Nov 2017 17:24:08 -0500 From: alexander.levin@verizon.com Cc: "M'boumba Cedric Madianga" , Vinod Koul , alexander.levin@verizon.com X-Host: endeavour.tdc.vzwcorp.com To: "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" Subject: [PATCH AUTOSEL for 4.9 05/54] dmaengine: stm32-dma: Fix null pointer dereference in stm32_dma_tx_status Thread-Topic: [PATCH AUTOSEL for 4.9 05/54] dmaengine: stm32-dma: Fix null pointer dereference in stm32_dma_tx_status Thread-Index: AQHTY+CDRXTyj+NPME+xtx7fHr070Q== Date: Wed, 22 Nov 2017 22:23:25 +0000 Message-ID: <20171122222246.19618-9-alexander.levin@verizon.com> References: <20171122222246.19618-1-alexander.levin@verizon.com> In-Reply-To: <20171122222246.19618-1-alexander.levin@verizon.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-messagesentrepresentingtype: 1 x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.144.60.250] Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by nfs id vAMNUHg4003723 From: M'boumba Cedric Madianga [ Upstream commit 57b5a32135c813f2ab669039fb4ec16b30cb3305 ] chan->desc is always set to NULL when a DMA transfer is complete. As a DMA transfer could be complete during the call of stm32_dma_tx_status, we need to be sure that chan->desc is not NULL before using this variable to avoid a null pointer deference issue. Signed-off-by: M'boumba Cedric Madianga Reviewed-by: Ludovic BARRE Signed-off-by: Vinod Koul Signed-off-by: Sasha Levin --- drivers/dma/stm32-dma.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) diff --git a/drivers/dma/stm32-dma.c b/drivers/dma/stm32-dma.c index bd758e67843c..ae3f60be7759 100644 --- a/drivers/dma/stm32-dma.c +++ b/drivers/dma/stm32-dma.c @@ -884,7 +884,7 @@ static enum dma_status stm32_dma_tx_status(struct dma_chan *c, struct virt_dma_desc *vdesc; enum dma_status status; unsigned long flags; - u32 residue; + u32 residue = 0; status = dma_cookie_status(c, cookie, state); if ((status == DMA_COMPLETE) || (!state)) @@ -892,16 +892,12 @@ static enum dma_status stm32_dma_tx_status(struct dma_chan *c, spin_lock_irqsave(&chan->vchan.lock, flags); vdesc = vchan_find_desc(&chan->vchan, cookie); - if (cookie == chan->desc->vdesc.tx.cookie) { + if (chan->desc && cookie == chan->desc->vdesc.tx.cookie) residue = stm32_dma_desc_residue(chan, chan->desc, chan->next_sg); - } else if (vdesc) { + else if (vdesc) residue = stm32_dma_desc_residue(chan, to_stm32_dma_desc(vdesc), 0); - } else { - residue = 0; - } - dma_set_residue(state, residue); spin_unlock_irqrestore(&chan->vchan.lock, flags); -- 2.11.0