From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f200.google.com (mail-wr0-f200.google.com [209.85.128.200]) by kanga.kvack.org (Postfix) with ESMTP id 17B616B002B for ; Fri, 9 Feb 2018 04:26:05 -0500 (EST) Received: by mail-wr0-f200.google.com with SMTP id n50so4217461wrn.20 for ; Fri, 09 Feb 2018 01:26:05 -0800 (PST) Received: from theia.8bytes.org (8bytes.org. [2a01:238:4383:600:38bc:a715:4b6d:a889]) by mx.google.com with ESMTPS id f13si515312edb.301.2018.02.09.01.26.03 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 09 Feb 2018 01:26:03 -0800 (PST) From: Joerg Roedel Subject: [PATCH 22/31] x86/mm/pti: Add an overflow check to pti_clone_pmds() Date: Fri, 9 Feb 2018 10:25:31 +0100 Message-Id: <1518168340-9392-23-git-send-email-joro@8bytes.org> In-Reply-To: <1518168340-9392-1-git-send-email-joro@8bytes.org> References: <1518168340-9392-1-git-send-email-joro@8bytes.org> Sender: owner-linux-mm@kvack.org List-ID: To: Thomas Gleixner , Ingo Molnar , "H . Peter Anvin" Cc: x86@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Linus Torvalds , Andy Lutomirski , Dave Hansen , Josh Poimboeuf , Juergen Gross , Peter Zijlstra , Borislav Petkov , Jiri Kosina , Boris Ostrovsky , Brian Gerst , David Laight , Denys Vlasenko , Eduardo Valentin , Greg KH , Will Deacon , aliguori@amazon.com, daniel.gruss@iaik.tugraz.at, hughd@google.com, keescook@google.com, Andrea Arcangeli , Waiman Long , Pavel Machek , jroedel@suse.de, joro@8bytes.org From: Joerg Roedel The addr counter will overflow if we clone the last PMD of the address space, resulting in an endless loop. Check for that and bail out of the loop when it happens. Signed-off-by: Joerg Roedel --- arch/x86/mm/pti.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/x86/mm/pti.c b/arch/x86/mm/pti.c index ce38f16..7f5e698 100644 --- a/arch/x86/mm/pti.c +++ b/arch/x86/mm/pti.c @@ -282,6 +282,10 @@ pti_clone_pmds(unsigned long start, unsigned long end, pmdval_t clear) p4d_t *p4d; pud_t *pud; + /* Overflow check */ + if (addr < start) + break; + pgd = pgd_offset_k(addr); if (WARN_ON(pgd_none(*pgd))) return; -- 2.7.4 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org