Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758377AbaGASZ5 (ORCPT ); Tue, 1 Jul 2014 14:25:57 -0400 Received: from mail-oa0-f48.google.com ([209.85.219.48]:47567 "EHLO mail-oa0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756911AbaGASZz (ORCPT ); Tue, 1 Jul 2014 14:25:55 -0400 MIME-Version: 1.0 In-Reply-To: <009301cf93f6$f938a270$eba9e750$%han@samsung.com> References: <1404084516-901-1-git-send-email-rickard_strandqvist@spectrumdigital.se> <1404084516-901-2-git-send-email-rickard_strandqvist@spectrumdigital.se> <009301cf93f6$f938a270$eba9e750$%han@samsung.com> Date: Tue, 1 Jul 2014 20:25:54 +0200 Message-ID: Subject: Re: [PATCH v2] i2c: busses: i2c-pxa.c: Fix for possible null pointer dereferenc From: Rickard Strandqvist To: Jingoo Han Cc: Wolfram Sang , Grant Likely , Rob Herring , Leilei Shang , Peter Korsgaard , linux-i2c@vger.kernel.org, "linux-kernel@vger.kernel.org" , "devicetree@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2014-06-30 2:05 GMT+02:00 Jingoo Han : > On Monday, June 30, 2014 8:29 AM, Rickard Strandqvist wrote: >> >> Fix for possible null pointer dereferenc, and there is a risk for memory leak in when something >> unexpected happens and the function returns. > > Would you split the patch into two patches? > > [PATCH 1/2] i2c: pxa: Fix for possible null pointer dereference > [PATCH 2/2] i2c: pxa: Use devm_* functions > >> >> 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..886877a 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; >> } >> >> /* 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; >> >> 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; >> } >> >> - 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; >> } >> >> 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; >> } >> >> - i2c->reg_base = ioremap(res->start, resource_size(res)); >> - if (!i2c->reg_base) { >> + i2c->reg_base = devm_ioremap(&dev->dev, res->start, resource_size(res)); >> + if (IS_ERR(i2c->reg_base)) { > > Did you check what devm_ioremap() returns? > It returns 'valid addr value' Or NULL as below. > So, IS_ERR() should NOT be used. > > ./lib/devres.c > > void __iomem *devm_ioremap(struct device *dev, resource_size_t offset, > unsigned long size) > { > void __iomem **ptr, *addr; > > ptr = devres_alloc(devm_ioremap_release, sizeof(*ptr), GFP_KERNEL); > if (!ptr) > return NULL; > > addr = ioremap(offset, size); > if (addr) { > *ptr = addr; > devres_add(dev, ptr); > } else > devres_free(ptr); > > return addr; > } > EXPORT_SYMBOL(devm_ioremap); > > Best regards, > Jingoo Han > >> ret = -EIO; >> - goto eremap; >> + goto emalloc; >> } >> >> 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; >> } >> >> 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); >> -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; >> } >> >> -- >> 1.7.10.4 > Hi Excuse my late reply. 1) A fix of the original error I made in my original patch. But it was completely different from this solution, you have trouble seeing it as something reasonable to do. My original patch: eclk: kfree(i2c); emalloc: - release_mem_region(res->start, resource_size(res)); + if(res) + release_mem_region(res->start, resource_size(res)); return ret; } 2) Wolfram Sang helped me with a patch example from commit 9b2b98a3b4de It hade this code below. I thought that it seem a little strange, but I trust Wolfram. - dev->virtbase = ioremap(adev->res.start, resource_size(&adev->res)); - if (!dev->virtbase) { + dev->virtbase = devm_ioremap(&adev->dev, adev->res.start, + resource_size(&adev->res)); + if (IS_ERR(dev->virtbase)) { ret = -ENOMEM; - goto err_no_ioremap; + goto err_no_mem; } Kind regards Rickard Strandqvist -- 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/