From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lorenzo Pieralisi Date: Fri, 16 Nov 2018 11:51:29 +0000 Subject: Re: [PATCH -next] PCI: dra7xx: Fix potential NULL dereference Message-Id: <20181116115129.GA3228@e107981-ln.cambridge.arm.com> 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> <20180120001645.GA21343@lenoch> In-Reply-To: <20180120001645.GA21343@lenoch> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Ladislav Michl , Wei Yongjun Cc: Bjorn Helgaas , Kishon Vijay Abraham I , Bjorn Helgaas , linux-omap@vger.kernel.org, linux-pci@vger.kernel.org, kernel-janitors@vger.kernel.org On Sat, Jan 20, 2018 at 01:16:45AM +0100, Ladislav Michl wrote: > 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 Wei, Ladislav, getting back to this old thread, I would mark it as "changes requested" and expect someone to post a follow-up patch, I do not think this is a solved problem. Lorenzo > 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)