From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AG47ELv9HGku4Ep7Qd0QtHPGqF9DiZqwYsuaP7C4pmUmItTwoMy57Ng+xzL2SIJQewUvonZ+6Q3c ARC-Seal: i=1; a=rsa-sha256; t=1521228611; cv=none; d=google.com; s=arc-20160816; b=Cx4n6yCxtL8q/99HBvKjhD7DjVslTuJMWj2kBNP+zjyQaz7o/OX71idjbOMxT+BWh2 kcrg8s9C2VlbDDJzYzwQsfHSXNmmtulVqlC933R430eBrUTD3lIEzslZY/hyjO4Za94h vMjyE0bvkYSjbGWCfXvgVhvsMGSfqob8OR7f/2OKvk7qJgQ3ETcbz+3I01V/FBegyZRy dGnXtrKyl+d7ci2d8HZxf+NRTPj2+ns02rUcrbR2HHlcRiR3x6iWfxLRy6qW+lkXp47Q JTiNj/jeG9ys7yNEnoI48A133IkOInTJyVVLcwkDdoVPVGHbLiQ2YavAtxpY7f9FJdO3 Rj9A== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature:arc-authentication-results; bh=S/IFyE5s2WbwnTT/5msmNTwuegueAW0gy7hAJnfhu+M=; b=R0/zQJSvg+X28SZf6xV+nViUqhuuImiNdwzisuOo4RvA0wR+vYG2MvKYArd6gMxDXh LoQife10UI5q/NHCe3Br5JUJxX56H+dLpnzwF3/18a5uR0UxuM+AWSb+jzl5u6p2IUCK lX53hJd5eSdrmTZjQMzqvGtoRfx1SeOAvTO4MsdLso0X09iK02dRaHAez/t8sY8BOb/w bn8+HHnPtncG18IVvgXBXITA+gASmdx1AGnwQMHdc5ec+qMl++F3tGsQQxAv3c8g8Ye1 aGj1VS361Ad9Wyup3+lJ2Kzj8xCziZrF9dEgotT0SMg82Xmo3dSqQl6zI+HG+A096y1t I6kw== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass (test mode) header.i=@8bytes.org header.s=mail-1 header.b=hF+xr0Gp; spf=pass (google.com: domain of joro@8bytes.org designates 81.169.241.247 as permitted sender) smtp.mailfrom=joro@8bytes.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=8bytes.org Authentication-Results: mx.google.com; dkim=pass (test mode) header.i=@8bytes.org header.s=mail-1 header.b=hF+xr0Gp; spf=pass (google.com: domain of joro@8bytes.org designates 81.169.241.247 as permitted sender) smtp.mailfrom=joro@8bytes.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=8bytes.org From: Joerg Roedel 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 Subject: [PATCH 24/35] x86/mm/pti: Add an overflow check to pti_clone_pmds() Date: Fri, 16 Mar 2018 20:29:42 +0100 Message-Id: <1521228593-3820-25-git-send-email-joro@8bytes.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1521228593-3820-1-git-send-email-joro@8bytes.org> References: <1521228593-3820-1-git-send-email-joro@8bytes.org> X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1595123813092757960?= X-GMAIL-MSGID: =?utf-8?q?1595123813092757960?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 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 8f53d21..96a690e 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