From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from zeeaster.vergenet.net (zeeaster.vergenet.net [206.189.110.174]) (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 E92B53232 for ; Thu, 19 Jan 2023 10:49:42 +0000 (UTC) Received: from momiji.horms.nl (86-93-216-223.fixed.kpn.net [86.93.216.223]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by zeeaster.vergenet.net (Postfix) with ESMTPSA id 1A182200A3; Thu, 19 Jan 2023 10:49:41 +0000 (UTC) Received: by momiji.horms.nl (Postfix, from userid 7100) id A69CC94047A; Thu, 19 Jan 2023 11:49:40 +0100 (CET) Date: Thu, 19 Jan 2023 11:49:40 +0100 From: Simon Horman To: Yuan Can Cc: gregkh@linuxfoundation.org, drv@mailo.com, damm+renesas@opensource.se, error27@gmail.com, linux-staging@lists.linux.dev Subject: Re: [PATCH v3] staging: emxx_udc: Add checks for dma_alloc_coherent() Message-ID: References: <20230119083119.16956-1-yuancan@huawei.com> Precedence: bulk X-Mailing-List: linux-staging@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230119083119.16956-1-yuancan@huawei.com> Organisation: Horms Solutions BV X-Virus-Scanned: clamav-milter 0.103.7 at zeeaster X-Virus-Status: Clean On Thu, Jan 19, 2023 at 08:31:19AM +0000, Yuan Can wrote: > As the dma_alloc_coherent may return NULL, the return value needs to be > checked to avoid NULL poineter dereference. > > Fixes: 33aa8d45a4fe ("staging: emxx_udc: Add Emma Mobile USB Gadget driver") > Signed-off-by: Yuan Can > --- > changes in v2: > - do the null pointer check right before the memcpy(). > changes in v3: > - do the null pointer check right after the dma_alloc_coherent(). > > drivers/staging/emxx_udc/emxx_udc.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) I am no longer associated with Renesas, as I was when the patch that added this problem was accepted. But, FWIIW, Reviewed-by: Simon Horman > > diff --git a/drivers/staging/emxx_udc/emxx_udc.c b/drivers/staging/emxx_udc/emxx_udc.c > index b4e19174bef2..f9765841c4aa 100644 > --- a/drivers/staging/emxx_udc/emxx_udc.c > +++ b/drivers/staging/emxx_udc/emxx_udc.c > @@ -2587,10 +2587,15 @@ static int nbu2ss_ep_queue(struct usb_ep *_ep, > req->unaligned = false; > > if (req->unaligned) { > - if (!ep->virt_buf) > + if (!ep->virt_buf) { > ep->virt_buf = dma_alloc_coherent(udc->dev, PAGE_SIZE, > &ep->phys_buf, > GFP_ATOMIC | GFP_DMA); > + if (!ep->virt_buf) { > + spin_unlock_irqrestore(&udc->lock, flags); > + return -ENOMEM; > + } > + } > if (ep->epnum > 0) { > if (ep->direct == USB_DIR_IN) > memcpy(ep->virt_buf, req->req.buf, > -- > 2.17.1 >