Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756052AbaGDJKV (ORCPT ); Fri, 4 Jul 2014 05:10:21 -0400 Received: from mail-la0-f52.google.com ([209.85.215.52]:38365 "EHLO mail-la0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751163AbaGDJKP (ORCPT ); Fri, 4 Jul 2014 05:10:15 -0400 Date: Fri, 4 Jul 2014 11:10:00 +0200 From: Emil Goode To: Rickard Strandqvist Cc: Wolfram Sang , Grant Likely , Rob Herring , Jingoo Han , Leilei Shang , Peter Korsgaard , linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org Subject: Re: [PATCH v3] i2c: busses: i2c-pxa.c: Fix for possible null pointer dereferenc Message-ID: <20140704091000.GA4738@lianli> References: <1404418756-10550-1-git-send-email-rickard_strandqvist@spectrumdigital.se> <1404418756-10550-2-git-send-email-rickard_strandqvist@spectrumdigital.se> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1404418756-10550-2-git-send-email-rickard_strandqvist@spectrumdigital.se> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello Rickard, Since this is a probe function there is also no need to release the devm_* resources in the i2c_pxa_remove function, this leads to double free. Also I have a few nit-pick comments below. On Thu, Jul 03, 2014 at 10:19:16PM +0200, Rickard Strandqvist wrote: > Fix for possible null pointer dereferenc, and there is a risk for memory leak if something unexpected happens and the function returns. > It now use Managed Device Resource instead. > > Signed-off-by: Rickard Strandqvist > --- > drivers/i2c/busses/i2c-pxa.c | 37 ++++++++++++++++--------------------- > 1 file changed, 16 insertions(+), 21 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-pxa.c b/drivers/i2c/busses/i2c-pxa.c > index be671f7..2edb633 100644 > --- a/drivers/i2c/busses/i2c-pxa.c > +++ b/drivers/i2c/busses/i2c-pxa.c > @@ -1141,10 +1141,10 @@ static int i2c_pxa_probe(struct platform_device *dev) > struct resource *res = NULL; > int ret, irq; > > - i2c = kzalloc(sizeof(struct pxa_i2c), GFP_KERNEL); > + i2c = devm_kzalloc(&dev->dev, sizeof(struct pxa_i2c), GFP_KERNEL); > if (!i2c) { > ret = -ENOMEM; > - goto emalloc; > + goto err_nothing_to_release; Perhaps its a good idea to return directly here, then the label err_nothing_to_release can be removed. > } > > /* Default adapter num to device id; i2c_pxa_probe_dt can override. */ > @@ -1154,18 +1154,19 @@ static int i2c_pxa_probe(struct platform_device *dev) > if (ret > 0) > ret = i2c_pxa_probe_pdata(dev, i2c, &i2c_type); > if (ret < 0) > - goto eclk; > + goto err_nothing_to_release; Same here. > > res = platform_get_resource(dev, IORESOURCE_MEM, 0); > irq = platform_get_irq(dev, 0); > if (res == NULL || irq < 0) { > ret = -ENODEV; > - goto eclk; > + goto err_nothing_to_release; Same here. > } > > - if (!request_mem_region(res->start, resource_size(res), res->name)) { > + if (!devm_request_mem_region(&dev->dev, res->start, > + resource_size(res), res->name)) { > ret = -ENOMEM; > - goto eclk; > + goto emalloc; We could also return directly here since the release_mem_region call should be removed, as mentioned in Jingoos reply. > } > > i2c->adap.owner = THIS_MODULE; > @@ -1176,16 +1177,16 @@ static int i2c_pxa_probe(struct platform_device *dev) > > strlcpy(i2c->adap.name, "pxa_i2c-i2c", sizeof(i2c->adap.name)); > > - i2c->clk = clk_get(&dev->dev, NULL); > + i2c->clk = devm_clk_get(&dev->dev, NULL); > if (IS_ERR(i2c->clk)) { > ret = PTR_ERR(i2c->clk); > - goto eclk; > + goto emalloc; Same here. > } > > - i2c->reg_base = ioremap(res->start, resource_size(res)); > - if (!i2c->reg_base) { > + i2c->reg_base = devm_ioremap_resource(&adev->dev, res)); > + if (IS_ERR(i2c->reg_base)) { > ret = -EIO; > - goto eremap; > + goto emalloc; Same here. > } > > i2c->reg_ibmr = i2c->reg_base + pxa_reg_layout[i2c_type].ibmr; > @@ -1227,10 +1228,10 @@ static int i2c_pxa_probe(struct platform_device *dev) > i2c->adap.algo = &i2c_pxa_pio_algorithm; > } else { > i2c->adap.algo = &i2c_pxa_algorithm; > - ret = request_irq(irq, i2c_pxa_handler, IRQF_SHARED, > - dev_name(&dev->dev), i2c); > + ret = devm_request_irq(&dev->dev, irq, i2c_pxa_handler, > + IRQF_SHARED, dev_name(&dev->dev), i2c); > if (ret) > - goto ereqirq; > + goto emalloc; Same here. > } > > i2c_pxa_reset(i2c); > @@ -1261,15 +1262,9 @@ static int i2c_pxa_probe(struct platform_device *dev) > eadapt: > if (!i2c->use_pio) > free_irq(irq, i2c); The free_irq() call should also be removed since devm_request_irq() was used. > -ereqirq: > - clk_disable_unprepare(i2c->clk); > - iounmap(i2c->reg_base); > -eremap: > - clk_put(i2c->clk); > -eclk: > - kfree(i2c); > emalloc: > release_mem_region(res->start, resource_size(res)); > +err_nothing_to_release: > return ret; > } > Best regards, Emil Goode -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/