Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753150AbcDVJv0 (ORCPT ); Fri, 22 Apr 2016 05:51:26 -0400 Received: from terminus.zytor.com ([198.137.202.10]:37144 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751831AbcDVJvX (ORCPT ); Fri, 22 Apr 2016 05:51:23 -0400 Date: Fri, 22 Apr 2016 02:47:53 -0700 From: tip-bot for Jan Beulich Message-ID: Cc: boris.ostrovsky@oracle.com, jbeulich@suse.com, bp@alien8.de, david.vrabel@citrix.com, torvalds@linux-foundation.org, brgerst@gmail.com, hpa@zytor.com, akpm@linux-foundation.org, JGross@suse.com, peterz@infradead.org, JBeulich@suse.com, dvlasenk@redhat.com, mingo@kernel.org, linux-kernel@vger.kernel.org, tglx@linutronix.de, vkuznets@redhat.com, toshi.kani@hp.com, luto@amacapital.net, xen-devel@lists.xenproject.org, mcgrof@suse.com Reply-To: mingo@kernel.org, dvlasenk@redhat.com, vkuznets@redhat.com, tglx@linutronix.de, linux-kernel@vger.kernel.org, toshi.kani@hp.com, xen-devel@lists.xenproject.org, luto@amacapital.net, mcgrof@suse.com, boris.ostrovsky@oracle.com, jbeulich@suse.com, david.vrabel@citrix.com, bp@alien8.de, torvalds@linux-foundation.org, akpm@linux-foundation.org, hpa@zytor.com, brgerst@gmail.com, peterz@infradead.org, JGross@suse.com, JBeulich@suse.com In-Reply-To: <57188ED802000078000E431C@prv-mh.provo.novell.com> References: <57188ED802000078000E431C@prv-mh.provo.novell.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/asm] x86/mm/xen: Suppress hugetlbfs in PV guests Git-Commit-ID: 103f6112f253017d7062cd74d17f4a514ed4485c X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2873 Lines: 73 Commit-ID: 103f6112f253017d7062cd74d17f4a514ed4485c Gitweb: http://git.kernel.org/tip/103f6112f253017d7062cd74d17f4a514ed4485c Author: Jan Beulich AuthorDate: Thu, 21 Apr 2016 00:27:04 -0600 Committer: Ingo Molnar CommitDate: Fri, 22 Apr 2016 10:05:00 +0200 x86/mm/xen: Suppress hugetlbfs in PV guests Huge pages are not normally available to PV guests. Not suppressing hugetlbfs use results in an endless loop of page faults when user mode code tries to access a hugetlbfs mapped area (since the hypervisor denies such PTEs to be created, but error indications can't be propagated out of xen_set_pte_at(), just like for various of its siblings), and - once killed in an oops like this: kernel BUG at .../fs/hugetlbfs/inode.c:428! invalid opcode: 0000 [#1] SMP ... RIP: e030:[] [] remove_inode_hugepages+0x25b/0x320 ... Call Trace: [] hugetlbfs_evict_inode+0x15/0x40 [] evict+0xbd/0x1b0 [] __dentry_kill+0x19a/0x1f0 [] dput+0x1fe/0x220 [] __fput+0x155/0x200 [] task_work_run+0x60/0xa0 [] do_exit+0x160/0x400 [] do_group_exit+0x3b/0xa0 [] get_signal+0x1ed/0x470 [] do_signal+0x14/0x110 [] prepare_exit_to_usermode+0xe9/0xf0 [] retint_user+0x8/0x13 This is CVE-2016-3961 / XSA-174. Reported-by: Vitaly Kuznetsov Signed-off-by: Jan Beulich Cc: Andrew Morton Cc: Andy Lutomirski Cc: Boris Ostrovsky Cc: Borislav Petkov Cc: Brian Gerst Cc: David Vrabel Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Juergen Gross Cc: Linus Torvalds Cc: Luis R. Rodriguez Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Toshi Kani Cc: stable@vger.kernel.org Cc: xen-devel Link: http://lkml.kernel.org/r/57188ED802000078000E431C@prv-mh.provo.novell.com Signed-off-by: Ingo Molnar --- arch/x86/include/asm/hugetlb.h | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/include/asm/hugetlb.h b/arch/x86/include/asm/hugetlb.h index f8a29d2..e6a8613 100644 --- a/arch/x86/include/asm/hugetlb.h +++ b/arch/x86/include/asm/hugetlb.h @@ -4,6 +4,7 @@ #include #include +#define hugepages_supported() cpu_has_pse static inline int is_hugepage_only_range(struct mm_struct *mm, unsigned long addr,