From mboxrd@z Thu Jan 1 00:00:00 1970 From: Frank Steiner Date: Thu, 30 Sep 2004 06:18:14 +0000 Subject: Re: Hanging udev process on nfs-mounted /dev Message-Id: <415BA526.8010905@bio.ifi.lmu.de> List-Id: References: <415980BF.1020401@bio.ifi.lmu.de> In-Reply-To: <415980BF.1020401@bio.ifi.lmu.de> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-hotplug@vger.kernel.org Kay Sievers wrote >>Seems we have two different problems here, one that sounds like a loop >>consuming all the CPU and onother one, like the trace, which looks like >>a F_SETLKW deadlock. >>The traces are indicating a deadlock, where processes are simply waiting >>for each other for a write-lock on the udev.tdb to be released. That would match my observation that there seemed to be 2-3 udev processes started almost at the same time. Since I recorded all the udev traces with the ppid in the log name, I could see that there were always three processes started close together (the log files having the same timestamp and the ppids not differing much, like pids 29465, 29470 and 29473), so they might deadlock. However, also note that these problems so far occured only on hosts having /dev/ mounted via NFS. Maybe the slow NFS traffic (in comparison to the local hard disk) is well-suited for triggering the deadlock. > Here is a patch that implements a timeout for the dead udev process. After > 20 seconds the lock system call is interrupted and the error debug from tdb > is logged to the syslog. I needed to port the sleep() calls, cause they > are not compatible with alarm(). Thanks for the patch, I will apply it and try to reproduce the situations! If I get a log, I will send it here. A general question: Someone on the NFS mailing list proposed to remove the NFS mount for dev and replace it by some tmpfs mounted on /dev. SuSE is not really prepared for it, so udevstart misses a lot of devices like /dev/stderr etc., but I could hack this myself easily. Is it safe to assume that one should have less problems with a tmpfs dev compared to a NFS mount? cu, Frank -- Dipl.-Inform. Frank Steiner Web: http://www.bio.ifi.lmu.de/~steiner/ Lehrstuhl f. Bioinformatik Mail: http://www.bio.ifi.lmu.de/~steiner/m/ LMU, Amalienstr. 17 Phone: +49 89 2180-4049 80333 Muenchen, Germany Fax: +49 89 2180-99-4049 * Rekursion kann man erst verstehen, wenn man Rekursion verstanden hat. * ------------------------------------------------------- This SF.net email is sponsored by: IT Product Guide on ITManagersJournal Use IT products in your business? Tell us what you think of them. Give us Your Opinions, Get Free ThinkGeek Gift Certificates! Click to find out more http://productguide.itmanagersjournal.com/guidepromo.tmpl _______________________________________________ Linux-hotplug-devel mailing list http://linux-hotplug.sourceforge.net Linux-hotplug-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-hotplug-devel