Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753553AbdDKVMV (ORCPT ); Tue, 11 Apr 2017 17:12:21 -0400 Received: from zeniv.linux.org.uk ([195.92.253.2]:55968 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753280AbdDKVMR (ORCPT ); Tue, 11 Apr 2017 17:12:17 -0400 Date: Tue, 11 Apr 2017 22:12:16 +0100 From: Al Viro To: Dave Jones , Linux Kernel Subject: Re: iov_iter_pipe warning. Message-ID: <20170411211216.GH29622@ZenIV.linux.org.uk> References: <20170321205901.mojmjd2fxmykq3df@codemonkey.org.uk> <20170410192800.GC29622@ZenIV.linux.org.uk> <20170410194206.loesu5licstif7or@codemonkey.org.uk> <20170410195711.GD29622@ZenIV.linux.org.uk> <20170410234830.tmqdhpjtfdveor3c@codemonkey.org.uk> <20170411002215.GE29622@ZenIV.linux.org.uk> <20170411030532.vcam25fz6224ny2h@codemonkey.org.uk> <20170411032839.GF29622@ZenIV.linux.org.uk> <20170411205336.uyz5vfw52twhh6ob@codemonkey.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170411205336.uyz5vfw52twhh6ob@codemonkey.org.uk> User-Agent: Mutt/1.7.1 (2016-10-04) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 587 Lines: 17 On Tue, Apr 11, 2017 at 04:53:36PM -0400, Dave Jones wrote: > > if (WARN_ON(pipe->nrbufs)) { > > printk(KERN_ERR "->splice_write = %p", > > sd->u.file->f_op->splice_write); > > } > > } > > Ah, missed adding this 2nd WARN_ON. Good - it means that we don't have to chase memory corruption yet. That smells like some ->splice_write() claiming it has copied more than it has drained from the pipe. > I'll turn it back off, and retry with the missing WARN from above added. Please, do. And it would be nice if you printed sd->u.file->f_op as well (in the same printk).