From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sc8-sf-mx2-b.sourceforge.net ([10.3.1.12] helo=sc8-sf-mx2.sourceforge.net) by sc8-sf-list1.sourceforge.net with esmtp (Exim 4.24) id 1AYHNT-0003Tn-1Q for user-mode-linux-devel@lists.sourceforge.net; Sun, 21 Dec 2003 20:09:07 -0800 Received: from mta9.adelphia.net ([68.168.78.199]) by sc8-sf-mx2.sourceforge.net with esmtp (Exim 4.24) id 1AYHNS-0000bL-Lh for user-mode-linux-devel@lists.sourceforge.net; Sun, 21 Dec 2003 20:09:06 -0800 From: Matt Zimmerman Subject: Re: [uml-devel] 2.4.22-[67] problems Message-ID: <20031222040857.GV9354@alcor.net> References: <20031220011323.GW18100@alcor.net> <20031220171450.GB10692@ccure.user-mode-linux.org> <20031221004742.GE9354@alcor.net> <200312211658.44353.blaisorblade_spam@yahoo.it> <20031221224001.GO9354@alcor.net> <20031221231638.GR9354@alcor.net> <200312220025.hBM0PlFI012918@ccure.user-mode-linux.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200312220025.hBM0PlFI012918@ccure.user-mode-linux.org> Sender: user-mode-linux-devel-admin@lists.sourceforge.net Errors-To: user-mode-linux-devel-admin@lists.sourceforge.net List-Unsubscribe: , List-Id: The user-mode Linux development list List-Post: List-Help: List-Subscribe: , List-Archive: Date: Sun, 21 Dec 2003 20:08:57 -0800 To: Jeff Dike Cc: user-mode-linux-devel@lists.sourceforge.net, 224431@bugs.debian.org, 224502@bugs.debian.org, debian-glibc@lists.debian.org On Sun, Dec 21, 2003 at 07:25:47PM -0500, Jeff Dike wrote: > mdz@debian.org said: > > I have just verified this myself. Building user-mode-linux > > 2.4.22-7um-1 on woody works fine (even when running on unstable), but > > building it on unstable does not. > > Conversely, does a unstable-built UML run on woody? The unstable-built UML is broken on woody as well. So far, my most reproducible test case so far (not 100%, but close) is to start up a netcat listener, and connect to it with input from /dev/zero, i.e. just push a bunch of data over a TCP connection. What happens is this: rootstrap:~# nc -v -l -p 1234 >/dev/null /dev/null > The one built on unstable randomly sees ENOSYS from certain system > > calls, such as select, read and mmap. > > Only those, or are there others that you can tell are failing? Offhand, I > don't see any commonality between those three, in terms of their interactions > with the host. Those are the ones that I have been able to easily identify. select came from the netcat test you see above. mmap was evident from the APT HTTP method: /usr/lib/apt/methods/http: error while loading shared libraries: libc.so.6: cannot map zero-fill pages: Error 38 (that error is from dl-load.c in glibc, and as far as I can tell indicates that mmap gave ENOSYS). basename from coreutils seemed to see write(2) failing: basename: write error: Function not implemented I also saw unlink do it, in dpkg: dpkg: error processing /var/cache/apt/archives/debhelper_4.0.2_all.deb (--unpack): failed to rmdir/unlink `/usr/share/man/man1/dh_compress.1.gz.dpkg-tmp': Function not implemented apt occasionally blows up read()ing from a socket as well: (none):~# apt-get update Get:1 http://debian woody/main Packages [1774kB] Err http://debian woody/main Packages Error reading from server - read (38 Function not implemented) Get:2 http://debian woody/main Release [95B] Fetched 95B in 0s (259B/s) Failed to fetch http://debian/dists/woody/main/binary-i386/Packages Error reading from server - read (38 Function not implemented) Reading Package Lists... Done Building Dependency Tree... Done E: Some index files failed to download, they have been ignored, or old ones used instead. > > I would appreciate any suggestions for how to track this problem down > > further. > > The randomness is strange. It suggests that somehow interrupts are getting > in the way. One possibility would be host system calls returning ENOSYS > instead of EINTR. I don't see much possibility that that's what's actually > happening, but that's the sort of thing I'd think about. Can you think of any way that userland changes could produce that kind of effect? I don't think I would know where to look. My kernel didn't change, and the problem seems to occur on different host kernels. I tried running UML under strace; this produces an impressive amount of output, but made it much more difficult to reproduce the bug. I finally got it to happen under strace, and I have a 226M logfile (7M gzipped) from the session, if you're interested in taking a look. I've put it up at http://people.debian.org/~mdz/temp/uml.strace.gz. I don't see any host system calls returning ENOSYS; the only failures are some very innocuous-looking EINTRs and a few EAGAINs that looks like they're associated with a terminal device. -- - mdz ------------------------------------------------------- This SF.net email is sponsored by: IBM Linux Tutorials. Become an expert in LINUX or just sharpen your skills. Sign up for IBM's Free Linux Tutorials. Learn everything from the bash shell to sys admin. Click now! http://ads.osdn.com/?ad_id=1278&alloc_id=3371&op=click _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel