From patchwork Thu Sep 9 14:59:38 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 12483361 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D70ACC433FE for ; Thu, 9 Sep 2021 15:00:02 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 70CF46113E for ; Thu, 9 Sep 2021 15:00:02 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 70CF46113E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id 3AF376B0073; Thu, 9 Sep 2021 11:00:00 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 3115D900002; Thu, 9 Sep 2021 11:00:00 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1187C6B0075; Thu, 9 Sep 2021 11:00:00 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0185.hostedemail.com [216.40.44.185]) by kanga.kvack.org (Postfix) with ESMTP id F28576B0073 for ; Thu, 9 Sep 2021 10:59:59 -0400 (EDT) Received: from smtpin36.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 972DC8249980 for ; Thu, 9 Sep 2021 14:59:59 +0000 (UTC) X-FDA: 78568344918.36.63ABBDD Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [216.205.24.124]) by imf26.hostedemail.com (Postfix) with ESMTP id 4112D20019C6 for ; Thu, 9 Sep 2021 14:59:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1631199598; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=87Mua4NbTS7oP3gkDXZZUnEGgyi6Qj+P+zd/pBlYJc8=; b=FpGBdYz/HjsO4EyPamMU62OuOTP78JvuHayIeLEHuzLvCBqz5ONw5qzY8TY//ocs3LLRKf 2JbvJSa+DvYCMNK9YRBFDHTLvtA4Z0YCvFcpE9fitLgOavZLVaWw2WYD9h0Q5wCMlxYEGB 5bBqpE/Wk1BMHEwi9RcKjaOnMkwk+So= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-147-7CI0ihIfP--BTgnMoCek5A-1; Thu, 09 Sep 2021 10:59:57 -0400 X-MC-Unique: 7CI0ihIfP--BTgnMoCek5A-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 2BC28BBEE5; Thu, 9 Sep 2021 14:59:56 +0000 (UTC) Received: from t480s.redhat.com (unknown [10.39.192.233]) by smtp.corp.redhat.com (Postfix) with ESMTP id 0203E1981F; Thu, 9 Sep 2021 14:59:54 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-s390@vger.kernel.org, kvm@vger.kernel.org, linux-mm@kvack.org, David Hildenbrand Subject: [PATCH RFC 2/9] s390/gmap: don't unconditionally call pte_unmap_unlock() in __gmap_zap() Date: Thu, 9 Sep 2021 16:59:38 +0200 Message-Id: <20210909145945.12192-3-david@redhat.com> In-Reply-To: <20210909145945.12192-1-david@redhat.com> References: <20210909145945.12192-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 4112D20019C6 X-Stat-Signature: zjyas3z4btriha5czh5u17b1mqbtpbrx Authentication-Results: imf26.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b="FpGBdYz/"; spf=none (imf26.hostedemail.com: domain of david@redhat.com has no SPF policy when checking 216.205.24.124) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=none) header.from=redhat.com X-HE-Tag: 1631199599-327555 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: ... 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 --- arch/s390/mm/gmap.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c index b6b56cd4ca64..9023bf3ced89 100644 --- a/arch/s390/mm/gmap.c +++ b/arch/s390/mm/gmap.c @@ -690,9 +690,10 @@ void __gmap_zap(struct gmap *gmap, unsigned long gaddr) /* 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);