From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D6573C433E2 for ; Wed, 9 Sep 2020 16:24:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A05182087C for ; Wed, 9 Sep 2020 16:24:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731011AbgIIQYB (ORCPT ); Wed, 9 Sep 2020 12:24:01 -0400 Received: from mail.kernel.org ([198.145.29.99]:45292 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731057AbgIIQX4 (ORCPT ); Wed, 9 Sep 2020 12:23:56 -0400 Received: from gaia (unknown [46.69.195.48]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id AE68B21D40; Wed, 9 Sep 2020 13:54:03 +0000 (UTC) Date: Wed, 9 Sep 2020 14:54:01 +0100 From: Catalin Marinas To: Lorenzo Pieralisi Cc: George Cherian , Yang Yingliang , "linux-kernel@vger.kernel.org" , "linux-pci@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "will.deacon@arm.com" , "bhelgaas@google.com" , "guohanjun@huawei.com" Subject: Re: [PATCH] arm64: PCI: fix memleak when calling pci_iomap/unmap() Message-ID: <20200909135400.GB13047@gaia> References: <20200907104546.GC26513@gaia> <20200907112118.GD26513@gaia> <20200909113613.GB6384@e121166-lin.cambridge.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200909113613.GB6384@e121166-lin.cambridge.arm.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Wed, Sep 09, 2020 at 12:36:13PM +0100, Lorenzo Pieralisi wrote: > On Mon, Sep 07, 2020 at 12:21:19PM +0100, Catalin Marinas wrote: > > On Mon, Sep 07, 2020 at 10:51:21AM +0000, George Cherian wrote: > > > Catalin Marinas wrote: > > > > On Sat, Sep 05, 2020 at 10:48:11AM +0800, Yang Yingliang wrote: > > > > > diff --git a/arch/arm64/kernel/pci.c b/arch/arm64/kernel/pci.c index > > > > > 1006ed2d7c604..ddfa1c53def48 100644 > > > > > --- a/arch/arm64/kernel/pci.c > > > > > +++ b/arch/arm64/kernel/pci.c > > > > > @@ -217,4 +217,9 @@ void pcibios_remove_bus(struct pci_bus *bus) > > > > > acpi_pci_remove_bus(bus); > > > > > } > > > > > > > > > > +void pci_iounmap(struct pci_dev *dev, void __iomem *addr) { > > > > > + iounmap(addr); > > > > > +} > > > > > +EXPORT_SYMBOL(pci_iounmap); > > > > > > > > So, what's wrong with the generic pci_iounmap() implementation? > > > > Shouldn't it call iounmap() already? > > > > > > Since ARM64 selects CONFIG_GENERIC_PCI_IOMAP and not > > > CONFIG_GENERIC_IOMAP, the pci_iounmap function is reduced to a NULL > > > function. Due to this, even the managed release variants or even the explicit > > > pci_iounmap calls doesn't really remove the mappings leading to leak. > > > > Ah, I missed the fact that pci_iounmap() depends on a different > > config option. > > > > > https://lkml.org/lkml/2020/8/20/28 > > > > So is this going to be fixed in the generic code? That would be my > > preference. > > > > A problem with the iounmap() in the proposed patch is that the region > > may have been an I/O port, so we could end up unmapping the I/O space. > > It boils down to finding a way to match a VA to a BAR resource so that > we can mirror on pci_iounmap() what's done in pci_iomap_range() (ie > check BAR resource flags to define how/if to unmap them), that would do > as a generic pci_iounmap() implementation. In the !CONFIG_GENERIC_IOMAP case (arm64), for IORESOURCE_IO, pci_iomap_range() calls __pci_ioport_map() which, with the default ioport_map(), it ends up with a simple PCI_IOBASE + (port & IO_SPACE_LIMIT). pci_iounmap() could check whether the pointer is in the PCI_IOBASE - PCI_IOBASE+IO_SPACE_LIMIT range before calling ioremap(), unless the arch code re-defined ioport_map. Something like below (not even compiled): diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h index dabf8cb7203b..fada420c9cd6 100644 --- a/include/asm-generic/io.h +++ b/include/asm-generic/io.h @@ -919,6 +919,11 @@ extern void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long max); #define pci_iounmap pci_iounmap static inline void pci_iounmap(struct pci_dev *dev, void __iomem *p) { +#ifndef ARCH_HAS_IOPORT_MAP + if (p >= PCI_IOBASE && p < PCI_IOBASE + IO_SPACE_LIMIT) + return; + iounmap(p); +#endif } #endif #endif /* CONFIG_GENERIC_IOMAP */ @@ -1009,7 +1014,9 @@ static inline void __iomem *ioremap_uc(phys_addr_t offset, size_t size) #ifdef CONFIG_HAS_IOPORT_MAP #ifndef CONFIG_GENERIC_IOMAP -#ifndef ioport_map +#ifdef ioport_map +#define ARCH_HAS_IOPORT_MAP +#else #define ioport_map ioport_map static inline void __iomem *ioport_map(unsigned long port, unsigned int nr) { -- Catalin