From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from bombadil.infradead.org ([198.137.202.133]:37598 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726366AbeLKPWn (ORCPT ); Tue, 11 Dec 2018 10:22:43 -0500 Date: Tue, 11 Dec 2018 07:22:41 -0800 From: Matthew Wilcox To: gregkh@linuxfoundation.org Cc: dan.j.williams@intel.com, jack@suse.cz, jthumshirn@suse.de, stable@vger.kernel.org Subject: Re: FAILED: patch "[PATCH] dax: Check page->mapping isn't NULL" failed to apply to 4.19-stable tree Message-ID: <20181211152241.GD6830@bombadil.infradead.org> References: <154453681519414@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <154453681519414@kroah.com> Sender: stable-owner@vger.kernel.org List-ID: On Tue, Dec 11, 2018 at 03:00:15PM +0100, gregkh@linuxfoundation.org wrote: > The patch below does not apply to the 4.19-stable tree. > If someone wants it applied there, or to any other stable or longterm > tree, then please email the backport, including the original git commit > id to . >>From ebcfdf7933e1c72dbe581e64064bc6b8bb5d8694 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Tue, 11 Dec 2018 09:41:48 -0500 Subject: [PATCH 1/2] dax: Check page->mapping isn't NULL 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 --- fs/dax.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/dax.c b/fs/dax.c index b0cd1364c68f..3a2682a6c832 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -423,7 +423,7 @@ bool dax_lock_mapping_entry(struct page *page) for (;;) { mapping = READ_ONCE(page->mapping); - if (!dax_mapping(mapping)) + if (!mapping || !dax_mapping(mapping)) break; /* -- 2.19.1