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[198.145.29.99]) by mx.google.com with ESMTPS id w23-v6si13841916ply.563.2018.05.28.04.07.39 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 28 May 2018 04:07:39 -0700 (PDT) Received-SPF: pass (google.com: domain of srs0=wbis=ip=linuxfoundation.org=gregkh@kernel.org designates 198.145.29.99 as permitted sender) client-ip=198.145.29.99; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=l5mTBeHH; spf=pass (google.com: domain of srs0=wbis=ip=linuxfoundation.org=gregkh@kernel.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=SRS0=WbIs=IP=linuxfoundation.org=gregkh@kernel.org Received: from localhost (LFbn-1-12247-202.w90-92.abo.wanadoo.fr [90.92.61.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 2217A20845; Mon, 28 May 2018 11:07:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1527505659; bh=BAFbYORoKcxMC27ivyYO8AZ+dK5wqUDS8tKaFKsD/L4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=l5mTBeHHGcaxAr55mMv4jzgtofwwtmTVx0yueJ7iqtd31ud+ZkIlcPHffynzf7dhF eyT5PFlCGZT6lBFh10Sw6doK9AsnrU2KXL4rkvihzrVkl8RXY4/mwX1PKWkMRoKGOG LzwJWbVxegJzXPbvxsj/+2rNJgz/XE8jG1tzNZx8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "David H. Gutteridge" , Joerg Roedel , Thomas Gleixner , Andrea Arcangeli , Andy Lutomirski , Boris Ostrovsky , Borislav Petkov , Brian Gerst , Dave Hansen , David Laight , Denys Vlasenko , Eduardo Valentin , Jiri Kosina , Josh Poimboeuf , Juergen Gross , Linus Torvalds , Pavel Machek , Peter Zijlstra , Waiman Long , Will Deacon , aliguori@amazon.com, daniel.gruss@iaik.tugraz.at, hughd@google.com, keescook@google.com, linux-mm@kvack.org, Ingo Molnar , Sasha Levin Subject: [PATCH 4.16 050/272] x86/pgtable: Dont set huge PUD/PMD on non-leaf entries Date: Mon, 28 May 2018 12:01:23 +0200 Message-Id: <20180528100245.071626281@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180528100240.256525891@linuxfoundation.org> References: <20180528100240.256525891@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: X-Virus-Scanned: ClamAV using ClamSMTP 4.16-stable review patch. If anyone has any objections, please let me know. ------------------ 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 @@ -1,6 +1,7 @@ // SPDX-License-Identifier: GPL-2.0 #include #include +#include #include #include #include @@ -636,6 +637,10 @@ 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( @@ -664,6 +669,10 @@ 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(