On Fri, Sep 30, 2011 at 10:29, James Hunt <james.hunt@xxxxxxxxxx> wrote: > I'm investigating a problem in Ubuntu Oneiric where we think udev messages maybe be getting lost due > to the way that we're stopping udevd: > > https://bugs.launchpad.net/ubuntu/+source/udev/+bug/818177 > > In summary, at the end of our initramfs, we are doing this: > > # Stop udevd, we'll miss a few events while we run init, but we catch up > udevadm control --exit > > # Move /dev to the real filesystem > mount -n -o move /dev ${rootmnt}/dev > > The problem is that most notably when using lvm2 the "--exit" call seems to be causing udev messages > relating to the *rootfs* to be lost so that the system fails to boot. > > Looking at udevd.c, it does the following when requested to exit: > > /* discard queued events and kill workers */ > event_queue_cleanup(udev, EVENT_QUEUED); > worker_kill(udev, 0); > > I'm currently trying to debug what is left in the queue to get a better handle on this, but I am > wondering if "udevadm control --exit" should request that udevd drain the queues rather than > discarding the messages for our case. Is the reason the messages are discarded to avoid slowing down > the boot coupled with the expectation that the caller will use "udevadm trigger" to catch up later? --exit just does a clean shutdown, it will not check for pending events, only already running stuff will be properly finished, but nothing new will be started. If you want queued stuff, queued in udevd or the kernel, to be all handled before exiting, add a call to 'settle' before the --exit call. Kay -- To unsubscribe from this list: send the line "unsubscribe linux-hotplug" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
