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=-20.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 54B83C47082 for ; Wed, 26 May 2021 22:57:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2ACB86113D for ; Wed, 26 May 2021 22:57:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233296AbhEZW6v (ORCPT ); Wed, 26 May 2021 18:58:51 -0400 Received: from mail.kernel.org ([198.145.29.99]:58458 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229939AbhEZW6v (ORCPT ); Wed, 26 May 2021 18:58:51 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 602CA6139A; Wed, 26 May 2021 22:57:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1622069839; bh=7dU95bxBcpCHYZ73t1oN4y6dORKEz3a/48R0GyJsQlE=; h=Date:From:To:Subject:From; b=0AEt/+tyLJVl8KmthYMfv2bM+myL1Um7dEftJihGZ1JsutnrVg0TOri+YkZVk9Xfe Jr4s6xoA8Q25NMDgJ9cTpEjhnAi8btDad+DYLkN4HvtrZpqImmtq5HHDxFBTeGesRj v1yweuQ/z+4AcpThpx9aeWaGReWPEFmKKaC7fC24= Date: Wed, 26 May 2021 15:57:17 -0700 From: akpm@linux-foundation.org To: adobriyan@gmail.com, alex.shi@linux.alibaba.com, david@redhat.com, guro@fb.com, haiyangz@microsoft.com, jasowang@redhat.com, jbohac@suse.cz, kys@microsoft.com, mhocko@suse.com, mike.kravetz@oracle.com, mm-commits@vger.kernel.org, mst@redhat.com, naoya.horiguchi@nec.com, osalvador@suse.de, rppt@linux.ibm.com, steven.price@arm.com, sthemmin@microsoft.com, wei.liu@kernel.org, willy@infradead.org, yaoaili@kingsoft.com Subject: + fs-proc-kcore-drop-kcore_remap-and-kcore_other.patch added to -mm tree Message-ID: <20210526225717.jbFSFkC_R%akpm@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: fs/proc/kcore: drop KCORE_REMAP and KCORE_OTHER has been added to the -mm tree. Its filename is fs-proc-kcore-drop-kcore_remap-and-kcore_other.patch This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/fs-proc-kcore-drop-kcore_remap-and-kcore_other.patch and later at https://ozlabs.org/~akpm/mmotm/broken-out/fs-proc-kcore-drop-kcore_remap-and-kcore_other.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: David Hildenbrand Subject: fs/proc/kcore: drop KCORE_REMAP and KCORE_OTHER Patch series "fs/proc/kcore: don't read offline sections, logically offline pages and hwpoisoned pages", v3. Looking for places where the kernel might unconditionally read PageOffline() pages, I stumbled over /proc/kcore; turns out /proc/kcore needs some more love to not touch some other pages we really don't want to read -- i.e., hwpoisoned ones. Examples for PageOffline() pages are pages inflated in a balloon, memory unplugged via virtio-mem, and partially-present sections in memory added by the Hyper-V balloon. When reading pages inflated in a balloon, we essentially produce unnecessary load in the hypervisor; holes in partially present sections in case of Hyper-V are not accessible and already were a problem for /proc/vmcore, fixed in makedumpfile by detecting PageOffline() pages. In the future, virtio-mem might disallow reading unplugged memory -- marked as PageOffline() -- in some environments, resulting in undefined behavior when accessed; therefore, I'm trying to identify and rework all these (corner) cases. With this series, there is really only access via /dev/mem, /proc/vmcore and kdb left after I ripped out /dev/kmem. kdb is an advanced corner-case use case -- we won't care for now if someone explicitly tries to do nasty things by reading from/writing to physical addresses we better not touch. /dev/mem is a use case we won't support for virtio-mem, at least for now, so we'll simply disallow mapping any virtio-mem memory via /dev/mem next. /proc/vmcore is really only a problem when dumping the old kernel via something that's not makedumpfile (read: basically never), however, we'll try sanitizing that as well in the second kernel in the future. Tested via kcore_dump: https://github.com/schlafwandler/kcore_dump This patch (of 6): Commit db779ef67ffe ("proc/kcore: Remove unused kclist_add_remap()") removed the last user of KCORE_REMAP. Commit 595dd46ebfc1 ("vfs/proc/kcore, x86/mm/kcore: Fix SMAP fault when dumping vsyscall user page") removed the last user of KCORE_OTHER. Let's drop both types. While at it, also drop vaddr in "struct kcore_list", used by KCORE_REMAP only. Link: https://lkml.kernel.org/r/20210526093041.8800-1-david@redhat.com Link: https://lkml.kernel.org/r/20210526093041.8800-2-david@redhat.com Signed-off-by: David Hildenbrand Reviewed-by: Mike Rapoport Cc: "Michael S. Tsirkin" Cc: Jason Wang Cc: Alexey Dobriyan Cc: "Matthew Wilcox (Oracle)" Cc: Oscar Salvador Cc: Michal Hocko Cc: Roman Gushchin Cc: Alex Shi Cc: Steven Price Cc: Mike Kravetz Cc: Aili Yao Cc: Jiri Bohac Cc: "K. Y. Srinivasan" Cc: Haiyang Zhang Cc: Stephen Hemminger Cc: Wei Liu Cc: Naoya Horiguchi Signed-off-by: Andrew Morton --- fs/proc/kcore.c | 7 ++----- include/linux/kcore.h | 3 --- 2 files changed, 2 insertions(+), 8 deletions(-) --- a/fs/proc/kcore.c~fs-proc-kcore-drop-kcore_remap-and-kcore_other +++ a/fs/proc/kcore.c @@ -380,11 +380,8 @@ read_kcore(struct file *file, char __use phdr->p_type = PT_LOAD; phdr->p_flags = PF_R | PF_W | PF_X; phdr->p_offset = kc_vaddr_to_offset(m->addr) + data_offset; - if (m->type == KCORE_REMAP) - phdr->p_vaddr = (size_t)m->vaddr; - else - phdr->p_vaddr = (size_t)m->addr; - if (m->type == KCORE_RAM || m->type == KCORE_REMAP) + phdr->p_vaddr = (size_t)m->addr; + if (m->type == KCORE_RAM) phdr->p_paddr = __pa(m->addr); else if (m->type == KCORE_TEXT) phdr->p_paddr = __pa_symbol(m->addr); --- a/include/linux/kcore.h~fs-proc-kcore-drop-kcore_remap-and-kcore_other +++ a/include/linux/kcore.h @@ -11,14 +11,11 @@ enum kcore_type { KCORE_RAM, KCORE_VMEMMAP, KCORE_USER, - KCORE_OTHER, - KCORE_REMAP, }; struct kcore_list { struct list_head list; unsigned long addr; - unsigned long vaddr; size_t size; int type; }; _ Patches currently in -mm which might be from david@redhat.com are perf-map_executable-does-not-indicate-vm_mayexec.patch binfmt-remove-in-tree-usage-of-map_executable.patch mm-ignore-map_executable-in-ksys_mmap_pgoff.patch fs-proc-kcore-drop-kcore_remap-and-kcore_other.patch fs-proc-kcore-pfn_is_ram-check-only-applies-to-kcore_ram.patch fs-proc-kcore-dont-read-offline-sections-logically-offline-pages-and-hwpoisoned-pages.patch mm-introduce-page_offline_beginendfreezethaw-to-synchronize-setting-pageoffline.patch virtio-mem-use-page_offline_startend-when-setting-pageoffline.patch fs-proc-kcore-use-page_offline_freezethaw.patch mm-make-variable-names-for-populate_vma_page_range-consistent.patch mm-madvise-introduce-madv_populate_readwrite-to-prefault-page-tables.patch maintainers-add-tools-testing-selftests-vm-to-memory-management.patch selftests-vm-add-protection_keys_32-protection_keys_64-to-gitignore.patch selftests-vm-add-test-for-madv_populate_readwrite.patch memory-hotplugrst-complete-admin-guide-overhaul.patch