From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ladislav Michl Date: Sat, 20 Jan 2018 00:16:45 +0000 Subject: Re: [PATCH -next] PCI: dra7xx: Fix potential NULL dereference Message-Id: <20180120001645.GA21343@lenoch> List-Id: References: <1516284037-81537-1-git-send-email-weiyongjun1@huawei.com> <20180118145420.GA21163@lenoch> <20180118183525.GG53542@bhelgaas-glaptop.roam.corp.google.com> <20180119095857.GA26765@lenoch> <20180119170657.GA27882@lenoch> In-Reply-To: <20180119170657.GA27882@lenoch> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Bjorn Helgaas Cc: Wei Yongjun , Kishon Vijay Abraham I , Lorenzo Pieralisi , Bjorn Helgaas , linux-omap@vger.kernel.org, linux-pci@vger.kernel.org, kernel-janitors@vger.kernel.org On Fri, Jan 19, 2018 at 06:06:57PM +0100, Ladislav Michl wrote: > On Fri, Jan 19, 2018 at 10:58:57AM +0100, Ladislav Michl wrote: > > On Thu, Jan 18, 2018 at 12:35:25PM -0600, Bjorn Helgaas wrote: > > > That's probably a better idea. Maybe we should add a comment like this > > > to help avoid this in the future: > > > > That seems to spot another a bit more serious problem (given how late > > release cycle is now). > > > > Both devm_ioremap() and devm_ioremap_resource() shares the same release > > function: devm_ioremap_release(). However this function is not aware of > > memory region previously requested by devm_request_mem_region() called > > from devm_ioremap_resource(). > > > > Bellow is just a quick hack, even untested as looking at devm_ioremap, > > devm_ioremap_wc and devm_ioremap_wc, there is some room for optimization. > > Okay, forget it, above analysis is not correct, however there is a bug (and > also in PCI version). To show it, let's make following modification: I will never ever work in single tree for two different boards without full recompile (which should save time and caused opposite) as it makes debugging pointless - there is no bug. As a request forgiveness, please accept following draft as proposed solution for $subj Subject: [PATCH] PCI: dra7xx: Use devm_ioremap_resource() diff --git a/drivers/pci/dwc/pci-dra7xx.c b/drivers/pci/dwc/pci-dra7xx.c index 8bf7c2714db6..7f422ae258ac 100644 --- a/drivers/pci/dwc/pci-dra7xx.c +++ b/drivers/pci/dwc/pci-dra7xx.c @@ -409,14 +409,14 @@ static int __init dra7xx_add_pcie_ep(struct dra7xx_pcie *dra7xx, ep->ops = &pcie_ep_ops; res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "ep_dbics"); - pci->dbi_base = devm_ioremap(dev, res->start, resource_size(res)); - if (!pci->dbi_base) - return -ENOMEM; + pci->dbi_base = devm_ioremap_resource(dev, res); + if (IS_ERR(pci->dbi_base)) + return PTR_ERR(pci->dbi_base); res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "ep_dbics2"); - pci->dbi_base2 = devm_ioremap(dev, res->start, resource_size(res)); - if (!pci->dbi_base2) - return -ENOMEM; + pci->dbi_base2 = devm_ioremap_resource(dev, res); + if (IS_ERR(pci->dbi_base2)) + return PTR_ERR(pci->dbi_base2); res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "addr_space"); if (!res)