Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751455AbdIRWE3 (ORCPT ); Mon, 18 Sep 2017 18:04:29 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:20781 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750790AbdIRWE1 (ORCPT ); Mon, 18 Sep 2017 18:04:27 -0400 Date: Mon, 18 Sep 2017 15:04:12 -0700 From: "Darrick J. Wong" To: Eric Sandeen Cc: Dave Chinner , Jens Axboe , Christoph Hellwig , Abdul Haleem , linuxppc-dev , linux-xfs , linux-next , linux-kernel , chandan Subject: Re: [linux-next][XFS][trinity] WARNING: CPU: 32 PID: 31369 at fs/iomap.c:993 Message-ID: <20170918220412.GB6533@magnolia> References: <1505746565.6990.18.camel@abdul.in.ibm.com> <20170918152706.GA11482@lst.de> <8abed401-1634-760f-6543-4652fa495315@kernel.dk> <20170918213143.GJ10621@dastard> <21c53d3f-5ca9-886d-a326-cb6f1bbddffd@sandeen.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <21c53d3f-5ca9-886d-a326-cb6f1bbddffd@sandeen.net> User-Agent: Mutt/1.5.24 (2015-08-30) X-Source-IP: aserv0022.oracle.com [141.146.126.234] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2175 Lines: 65 On Mon, Sep 18, 2017 at 05:00:58PM -0500, Eric Sandeen wrote: > On 9/18/17 4:31 PM, Dave Chinner wrote: > > On Mon, Sep 18, 2017 at 09:28:55AM -0600, Jens Axboe wrote: > >> On 09/18/2017 09:27 AM, Christoph Hellwig wrote: > >>> On Mon, Sep 18, 2017 at 08:26:05PM +0530, Abdul Haleem wrote: > >>>> Hi, > >>>> > >>>> A warning is triggered from: > >>>> > >>>> file fs/iomap.c in function iomap_dio_rw > >>>> > >>>> if (ret) > >>>> goto out_free_dio; > >>>> > >>>> ret = invalidate_inode_pages2_range(mapping, > >>>> start >> PAGE_SHIFT, end >> PAGE_SHIFT); > >>>>>> WARN_ON_ONCE(ret); > >>>> ret = 0; > >>>> > >>>> inode_dio_begin(inode); > >>> > >>> This is expected and an indication of a problematic workload - which > >>> may be triggered by a fuzzer. > >> > >> If it's expected, why don't we kill the WARN_ON_ONCE()? I get it all > >> the time running xfstests as well. > > > > Because when a user reports a data corruption, the only evidence we > > have that they are running an app that does something stupid is this > > warning in their syslogs. Tracepoints are not useful for replacing > > warnings about data corruption vectors being triggered. > > Is the full WARN_ON spew really helpful to us, though? Certainly > the user has no idea what it means, and will come away terrified > but none the wiser. > > Would a more informative printk_once() still give us the evidence > without the ZOMG I THINK I OOPSED that a WARN_ON produces? Or do we > want/need the backtrace? Maybe we could state a little more directly what's going on: if (err) printk_once(KERN_INFO "Urk, collision detected between direct IO and page cache, YHL. HAND.\n"); ? 8-) --D > > -Eric > > > It needs to be on by default, bu tI'm sure we can wrap it with > > something like an xfs_alert_tag() type of construct so the tag can > > be set in /proc/fs/xfs/panic_mask to suppress it if testers so > > desire. > > > > Cheers, > > > > Dave. > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-next" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html