From mboxrd@z Thu Jan 1 00:00:00 1970 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=-6.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 9D7FBC6786C for ; Fri, 14 Dec 2018 12:36:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 634AC208E7 for ; Fri, 14 Dec 2018 12:36:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1544790986; bh=q3VW0EhI6kg7jaxsPySNJnDmvdPTMn1yoijvbGTj1aU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=gIwBOeQuwhrlw+GcQZhJ9hU+0MpWFr9MlA2kbfy9EtuLUxvScABtcseWjKVsqbSj5 /bLYAzfeoGn9FTb/ktYR67T5HERVpec4V+z8BegMVAhTrCK6SlstLVc31Juub2Weig +FHBIOrpPA1z8L9tbs+WyGk5X4+rFme8kEzo/OMs= DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 634AC208E7 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730474AbeLNMgZ (ORCPT ); Fri, 14 Dec 2018 07:36:25 -0500 Received: from mail.kernel.org ([198.145.29.99]:51836 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730970AbeLNMGm (ORCPT ); Fri, 14 Dec 2018 07:06:42 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (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 783BA2147D; Fri, 14 Dec 2018 12:06:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1544789201; bh=q3VW0EhI6kg7jaxsPySNJnDmvdPTMn1yoijvbGTj1aU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=lWbv/isSKp3Upyef94HSo1c7vzAhXxYkPt2oIjkGJg7fJiktK0bkWzN4nlyFgvYxM 7a1bWLOZii0RGYc8SVj3uHZa/YyqAnfX0Y14Ao9GISACVJYxooInY7SopYlsoYeNT2 WqTVd09gA+Y9ARqz7vW5aK3CSfqncFA1nWzphJQk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jan Kara , Matthew Wilcox , Johannes Thumshirn , Dan Williams Subject: [PATCH 4.19 134/142] dax: Check page->mapping isnt NULL Date: Fri, 14 Dec 2018 13:00:19 +0100 Message-Id: <20181214115752.395057974@linuxfoundation.org> X-Mailer: git-send-email 2.20.0 In-Reply-To: <20181214115747.053633987@linuxfoundation.org> References: <20181214115747.053633987@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Matthew Wilcox commit c93db7bb6ef3251e0ea48ade311d3e9942748e1c upstream. If we race with inode destroy, it's possible for page->mapping to be NULL before we even enter this routine, as well as after having slept waiting for the dax entry to become unlocked. Fixes: c2a7d2a11552 ("filesystem-dax: Introduce dax_lock_mapping_entry()") Cc: Reported-by: Jan Kara Signed-off-by: Matthew Wilcox Reviewed-by: Johannes Thumshirn Reviewed-by: Jan Kara Signed-off-by: Dan Williams Signed-off-by: Greg Kroah-Hartman --- fs/dax.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/fs/dax.c +++ b/fs/dax.c @@ -423,7 +423,7 @@ bool dax_lock_mapping_entry(struct page for (;;) { mapping = READ_ONCE(page->mapping); - if (!dax_mapping(mapping)) + if (!mapping || !dax_mapping(mapping)) break; /*