Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Wed, 27 Jun 2018 13:44:38 -0600
From:   Ross Zwisler <ross.zwisler@linux.intel.com>
To:     Matthew Wilcox <willy@infradead.org>
Cc:     Ross Zwisler <ross.zwisler@linux.intel.com>, linux-mm@kvack.org,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        Jan Kara <jack@suse.cz>, Jeff Layton <jlayton@redhat.com>,
        Lukas Czerner <lczerner@redhat.com>,
        Christoph Hellwig <hch@lst.de>,
        Goldwyn Rodrigues <rgoldwyn@suse.com>,
        Nicholas Piggin <npiggin@gmail.com>,
        Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>,
        linux-nilfs@vger.kernel.org, Jaegeuk Kim <jaegeuk@kernel.org>,
        Chao Yu <yuchao0@huawei.com>,
        linux-f2fs-devel@lists.sourceforge.net
Subject: Re: [PATCH v14 00/74] Convert page cache to XArray
Message-ID: <20180627194438.GA20774@linux.intel.com>
Mail-Followup-To: Ross Zwisler <ross.zwisler@linux.intel.com>,
        Matthew Wilcox <willy@infradead.org>, linux-mm@kvack.org,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        Jan Kara <jack@suse.cz>, Jeff Layton <jlayton@redhat.com>,
        Lukas Czerner <lczerner@redhat.com>, Christoph Hellwig <hch@lst.de>,
        Goldwyn Rodrigues <rgoldwyn@suse.com>,
        Nicholas Piggin <npiggin@gmail.com>,
        Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>,
        linux-nilfs@vger.kernel.org, Jaegeuk Kim <jaegeuk@kernel.org>,
        Chao Yu <yuchao0@huawei.com>,
        linux-f2fs-devel@lists.sourceforge.net
References: <20180617020052.4759-1-willy@infradead.org>
 <20180619031257.GA12527@linux.intel.com>
 <20180619092230.GA1438@bombadil.infradead.org>
 <20180619164037.GA6679@linux.intel.com>
 <20180619171638.GE1438@bombadil.infradead.org>
 <20180627110529.GA19606@bombadil.infradead.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20180627110529.GA19606@bombadil.infradead.org>
User-Agent: Mutt/1.9.2 (2017-12-15)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Wed, Jun 27, 2018 at 04:05:29AM -0700, Matthew Wilcox wrote:
> On Tue, Jun 19, 2018 at 10:16:38AM -0700, Matthew Wilcox wrote:
> > I think I see a bug.  No idea if it's the one you're hitting ;-)
> > 
> > I had been intending to not use the 'entry' to decide whether we were
> > waiting on a 2MB or 4kB page, but rather the xas.  I shelved that idea,
> > but not before dropping the DAX_PMD flag being passed from the PMD
> > pagefault caller.  So if I put that back ...
> 
> Did you get a chance to test this?

With this patch it doesn't deadlock, but the test dies with a SIGBUS and we
hit a WARN_ON in the DAX code:

WARNING: CPU: 5 PID: 1678 at fs/dax.c:226 get_unlocked_entry+0xf7/0x120

I don't have a lot of time this week to debug further.  The quickest path to
victory is probably for you to get this reproducing in your test setup.  Does
XFS + DAX + generic/340 pass for you?