Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B1827C433EF for ; Wed, 24 Nov 2021 12:38:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343826AbhKXMlO (ORCPT ); Wed, 24 Nov 2021 07:41:14 -0500 Received: from mail.kernel.org ([198.145.29.99]:37806 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244821AbhKXMiH (ORCPT ); Wed, 24 Nov 2021 07:38:07 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3F63C6108E; Wed, 24 Nov 2021 12:22:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1637756567; bh=baaVK/Zb7EIU26LQm3JnjMNmjQroIBMHomQCgwJALIE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mvtfvUtI1weuJ689vsyNFtUwgda7vqTeSOwDsUhpWfj51Q1yTvc+K94ScJCt5cDUD H6M6xGOMWXq2AC9KWsSJM2CRM9EpNraAXRlIbuhaKFpSdN2Cx0RL3TBqdAGpYw35/X d7zPlKsRioAzNOPDaeQmHdcIWCk88F01TubtU1FE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, David Hildenbrand , Claudio Imbrenda , Heiko Carstens , Christian Borntraeger , Sasha Levin Subject: [PATCH 4.14 130/251] s390/gmap: dont unconditionally call pte_unmap_unlock() in __gmap_zap() Date: Wed, 24 Nov 2021 12:56:12 +0100 Message-Id: <20211124115714.767418511@linuxfoundation.org> X-Mailer: git-send-email 2.34.0 In-Reply-To: <20211124115710.214900256@linuxfoundation.org> References: <20211124115710.214900256@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: David Hildenbrand [ Upstream commit b159f94c86b43cf7e73e654bc527255b1f4eafc4 ] ... otherwise we will try unlocking a spinlock that was never locked via a garbage pointer. At the time we reach this code path, we usually successfully looked up a PGSTE already; however, evil user space could have manipulated the VMA layout in the meantime and triggered removal of the page table. Fixes: 1e133ab296f3 ("s390/mm: split arch/s390/mm/pgtable.c") Signed-off-by: David Hildenbrand Reviewed-by: Claudio Imbrenda Acked-by: Heiko Carstens Link: https://lore.kernel.org/r/20210909162248.14969-3-david@redhat.com Signed-off-by: Christian Borntraeger Signed-off-by: Sasha Levin --- arch/s390/mm/gmap.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/arch/s390/mm/gmap.c +++ b/arch/s390/mm/gmap.c @@ -665,9 +665,10 @@ void __gmap_zap(struct gmap *gmap, unsig vmaddr |= gaddr & ~PMD_MASK; /* Get pointer to the page table entry */ ptep = get_locked_pte(gmap->mm, vmaddr, &ptl); - if (likely(ptep)) + if (likely(ptep)) { ptep_zap_unused(gmap->mm, vmaddr, ptep, 0); - pte_unmap_unlock(ptep, ptl); + pte_unmap_unlock(ptep, ptl); + } } } EXPORT_SYMBOL_GPL(__gmap_zap);