On Tue, Mar 6, 2012 at 13:13, Andrew Wagin <avagin@xxxxxxxxx> wrote: > 2012/3/6 Kay Sievers <kay.sievers@xxxxxxxx>: >> On Tue, Mar 6, 2012 at 09:48, Andrey Vagin <avagin@xxxxxxxxx> wrote: >>> From: Andrey Vagin <avagin@xxxxxxxxxx> >>> >>> A kernel gives events, but this events can be unsorted. >>> For example, here is log from system: >>> udevd[77]: seq 924 queued, 'add' 'bdi' >>> udevd[77]: seq 926 queued, 'add' 'block' >>> udevd[77]: seq 927 queued, 'add' 'block' >>> udevd[77]: seq 928 queued, 'add' 'block >>> udevd[77]: seq 925 queued, 'add' 'drivers' >> >> The kernel cannot send un-ordered events. Please try to reproduce that >> with 'udevadm monitor'. > > I can't reproduce this bug, because I have not this host already. > I've attached the console.log. I have not other logs. > I showed you messages from event_queue_insert(). Actually it's what you ask. > I suppose that a kernel should not send un-ordered events, but it does. > > Let's look at kobject_uevent_env() in kernel source: > > spin_lock(&sequence_lock); > seq = ++uevent_seqnum; > spin_unlock(&sequence_lock); > > .... <-- here someone can send its event > > /* send netlink message */ > mutex_lock(&uevent_sock_mutex); > ..... > > I want to say that code contains a window between incrementing seqnum > and sending an event. Yeah, that looks suspicious. We need to find out what and how to fix that. The queue handling in the daemon assumes that the events are ordered, so there might not only a problem with 'settle'. 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
