From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Fri, 3 May 2002 03:31:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 3 May 2002 03:31:56 -0400 Received: from supreme.pcug.org.au ([203.10.76.34]:21934 "EHLO pcug.org.au") by vger.kernel.org with ESMTP id ; Fri, 3 May 2002 03:31:55 -0400 Date: Fri, 3 May 2002 17:31:09 +1000 From: Stephen Rothwell To: Andrew Burgess Cc: linux-kernel@vger.kernel.org Subject: Re: dnotify oddity in 2.4.19pre6aa1 Message-Id: <20020503173109.1afdbec1.sfr@canb.auug.org.au> In-Reply-To: <200204231658.g3NGwE203196@athlon.cichlid.com> X-Mailer: Sylpheed version 0.7.4 (GTK+ 1.2.10; i386-debian-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi Andrew, Sorry I have been a bit slow on this. On Tue, 23 Apr 2002 09:58:14 -0700 Andrew Burgess wrote: > > I am seeing something very strange with the dnotify feature in kernel > 2.4.19pre6aa1. I'm developing a file copy daemon that makes backups of > files as soon as they change so I run dnotify on every directory in my > system (essentially). I based my program on the example in dnotify.txt > in the Documentation directory. So far, so good :-) > I notice that after a while two things happen: > > 1) In my copyd process I start getting signals for directories that are > not changing. Even stranger, I get signals for fd that I've never > opened. OK, this is weird, but I am looking into it. > 2) Other processes, like sendmail, start exiting with the same signal > (RTMIN+5). (I use +5 because I started seeing the problem with +0 and I > took a wild guess that RTMIN+0 was being used for something else). Does your copyd fork and exit after it has enabled the dnotify? Is it still running when other processes start being killed? > This does not seem to happen if I reboot and do not restart my copyd > process. > > My system does cycle through process descriptors every few minutes (lots > of short lived server processes) and sendmail also runs through pids > rapidly. > > I'm wondering if something isn't being properly reset or cleared when a > process exits so when the same process or fd data structure (or > whatever) is reused inside the kernel the signals are still active > somehow? This is a SMP Athlon, perhaps an SMP race? That is a possibility, although I thought we had stomped on this bug. > Do I need to configure something more in my kernel? I don't see any > config options for realtime or rt or anything like that. And it does > work fine after a reboot. No, should be fine. Can you send me a copy of your copyd (or the relevant subparts of it), please? -- Cheers, Stephen Rothwell sfr@canb.auug.org.au http://www.canb.auug.org.au/~sfr/