From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.136]:55720 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752081AbbLDWnj (ORCPT ); Fri, 4 Dec 2015 17:43:39 -0500 Date: Fri, 4 Dec 2015 16:43:34 -0600 From: Bjorn Helgaas To: Dongdong Liu Cc: wangzhou1@hisilicon.com, linux-pci@vger.kernel.org, bhelgaas@google.com, gabriele.paoloni@huawei.com, qiujiang@huawei.com, zhangjukuo@huawei.com, haifeng.wei@huawei.com, yisen.zhuang@huawei.com Subject: Re: [PATCH] PCI: hisi: fix the hisi_pcie_cfg_read bug when size=4 Message-ID: <20151204224334.GL20125@localhost> References: <1448600280-83695-1-git-send-email-liudongdong3@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1448600280-83695-1-git-send-email-liudongdong3@huawei.com> Sender: linux-pci-owner@vger.kernel.org List-ID: On Fri, Nov 27, 2015 at 12:58:00PM +0800, Dongdong Liu wrote: > Current hisi_pcie_cfg_read code read the RC configuration space, > this has a problem that the output parameter "*val" have not been > assigned when size=4, so we fix the bug by "*val = reg_val" when size=4. > > Signed-off-by: Dongdong Liu Wow, that's a pretty egregious bug. Was the hisi driver ever tested at all? We use dword reads in pci_bus_read_dev_vendor_id() to enumerate devices, so if those didn't return valid data, nothing at all should have worked. I tentatively put this on my for-linus branch for v4.4, but I wonder whether it might be smarter to revert the driver completely until I have more confidence in it. What sort of testing have you done on this driver? > --- > drivers/pci/host/pcie-hisi.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/pci/host/pcie-hisi.c b/drivers/pci/host/pcie-hisi.c > index 35457ec..da677b1 100644 > --- a/drivers/pci/host/pcie-hisi.c > +++ b/drivers/pci/host/pcie-hisi.c > @@ -61,7 +61,9 @@ static int hisi_pcie_cfg_read(struct pcie_port *pp, int where, int size, > *val = *(u8 __force *) walker; > else if (size == 2) > *val = *(u16 __force *) walker; > - else if (size != 4) > + else if (size == 4) > + *val = reg_val; > + else > return PCIBIOS_BAD_REGISTER_NUMBER; > > return PCIBIOS_SUCCESSFUL; > -- > 1.9.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-pci" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html