From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f69.google.com (mail-pg0-f69.google.com [74.125.83.69]) by kanga.kvack.org (Postfix) with ESMTP id E4EFC6B0003 for ; Wed, 2 May 2018 15:07:24 -0400 (EDT) Received: by mail-pg0-f69.google.com with SMTP id m13-v6so10753679pgp.5 for ; Wed, 02 May 2018 12:07:24 -0700 (PDT) Received: from mail.kernel.org (mail.kernel.org. [198.145.29.99]) by mx.google.com with ESMTPS id x17si11895111pfm.330.2018.05.02.12.07.23 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 02 May 2018 12:07:23 -0700 (PDT) Subject: Patch "x86/pgtable: Don't set huge PUD/PMD on non-leaf entries" has been added to the 4.4-stable tree From: Date: Wed, 02 May 2018 12:04:18 -0700 Message-ID: <152528785812887@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org List-ID: To: 20180411152437.GC15462@8bytes.org, David.Laight@aculab.com, aarcange@redhat.com, alexander.levin@microsoft.com, aliguori@amazon.com, boris.ostrovsky@oracle.com, bp@alien8.de, brgerst@gmail.com, daniel.gruss@iaik.tugraz.at, dave.hansen@intel.com, dhgutteridge@sympatico.ca, dvlasenk@redhat.com, eduval@amazon.com, gregkh@linuxfoundation.org, hughd@google.com, jgross@suse.com, jkosina@suse.cz, joro@8bytes.org, jpoimboe@redhat.com, jroedel@suse.de, keescook@google.com, linux-mm@kvack.org, llong@redhat.com, luto@kernel.org, mingo@kernel.org, pavel@ucw.cz, peterz@infradead.org, tglx@linutronix.de, torvalds@linux-foundation.org, will.deacon@arm.com Cc: stable-commits@vger.kernel.org This is a note to let you know that I've just added the patch titled x86/pgtable: Don't set huge PUD/PMD on non-leaf entries to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: x86-pgtable-don-t-set-huge-pud-pmd-on-non-leaf-entries.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From foo@baz Wed May 2 11:39:22 PDT 2018 From: Joerg Roedel Date: Wed, 11 Apr 2018 17:24:38 +0200 Subject: x86/pgtable: Don't set huge PUD/PMD on non-leaf entries From: Joerg Roedel [ Upstream commit e3e288121408c3abeed5af60b87b95c847143845 ] The pmd_set_huge() and pud_set_huge() functions are used from the generic ioremap() code to establish large mappings where this is possible. But the generic ioremap() code does not check whether the PMD/PUD entries are already populated with a non-leaf entry, so that any page-table pages these entries point to will be lost. Further, on x86-32 with SHARED_KERNEL_PMD=0, this causes a BUG_ON() in vmalloc_sync_one() when PMD entries are synced from swapper_pg_dir to the current page-table. This happens because the PMD entry from swapper_pg_dir was promoted to a huge-page entry while the current PGD still contains the non-leaf entry. Because both entries are present and point to a different page, the BUG_ON() triggers. This was actually triggered with pti-x32 enabled in a KVM virtual machine by the graphics driver. A real and better fix for that would be to improve the page-table handling in the generic ioremap() code. But that is out-of-scope for this patch-set and left for later work. Reported-by: David H. Gutteridge Signed-off-by: Joerg Roedel Reviewed-by: Thomas Gleixner Cc: Andrea Arcangeli Cc: Andy Lutomirski Cc: Boris Ostrovsky Cc: Borislav Petkov Cc: Brian Gerst Cc: Dave Hansen Cc: David Laight Cc: Denys Vlasenko Cc: Eduardo Valentin Cc: Greg KH Cc: Jiri Kosina Cc: Josh Poimboeuf Cc: Juergen Gross Cc: Linus Torvalds Cc: Pavel Machek Cc: Peter Zijlstra Cc: Waiman Long Cc: Will Deacon Cc: aliguori@amazon.com Cc: daniel.gruss@iaik.tugraz.at Cc: hughd@google.com Cc: keescook@google.com Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20180411152437.GC15462@8bytes.org Signed-off-by: Ingo Molnar Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- arch/x86/mm/pgtable.c | 9 +++++++++ 1 file changed, 9 insertions(+) --- a/arch/x86/mm/pgtable.c +++ b/arch/x86/mm/pgtable.c @@ -1,5 +1,6 @@ #include #include +#include #include #include #include @@ -600,6 +601,10 @@ int pud_set_huge(pud_t *pud, phys_addr_t (mtrr != MTRR_TYPE_WRBACK)) return 0; + /* Bail out if we are we on a populated non-leaf entry: */ + if (pud_present(*pud) && !pud_huge(*pud)) + return 0; + prot = pgprot_4k_2_large(prot); set_pte((pte_t *)pud, pfn_pte( @@ -628,6 +633,10 @@ int pmd_set_huge(pmd_t *pmd, phys_addr_t return 0; } + /* Bail out if we are we on a populated non-leaf entry: */ + if (pmd_present(*pmd) && !pmd_huge(*pmd)) + return 0; + prot = pgprot_4k_2_large(prot); set_pte((pte_t *)pmd, pfn_pte( Patches currently in stable-queue which might be from joro@8bytes.org are queue-4.4/x86-apic-set-up-through-local-apic-mode-on-the-boot-cpu-if-noapic-specified.patch queue-4.4/x86-pgtable-don-t-set-huge-pud-pmd-on-non-leaf-entries.patch