Hi! > When udev kills its worker due to timeout - so udev rules was not finished > within predefined timeout (which unfortunately changes according to mind > change of udev developer - so it ranges from 90seconds to 300seconds depending > on date of release) - you need to look out for reason why the timeout happens > - > > - is it because disk read was dead ? > > - is it because it's overloaded system ? > > - is it because of slow read operation (i.e. some raid arrays are known to > wake-up slowly) > > - was udev rule accessing something it shouldn't even read ?
Thanks for these hints. Next time, I will collect the udev events while trying to reproduce. Again, I reproduced this on centos 7.6 with lvm2-1.02.180, full log file will be attached. > > Once you know this - you can decide what's the best solution - you can > extended default timeout to larger value (i.e. 300 used to be usually good > for this case) you can fix/replace your failing drive. When lvcreate hangs, the /dev/dm-26 has been visible, but the /dev/vg0/22 symbol link is not ready. Abstracted from the log, it waits for the udev cookie count to become zero: """ libdm-common.c:2433 lvcreate Udev cookie 0xd4d0b57 (semid 225214464) created libdm-common.c:2453 lvcreate Udev cookie 0xd4d0b57 (semid 225214464) incremented to 1 libdm-common.c:2325 lvcreate Udev cookie 0xd4d0b57 (semid 225214464) incremented to 2 libdm-common.c:2575 lvcreate Udev cookie 0xd4d0b57 (semid 225214464) assigned to RESUME task(5) with flags DISABLE_LIBRARY_FALLBACK (0x20) ... libdm-deptree.c:1302 lvcreate Resuming vg0-22 (252:26). ... libdm-common.c:2325 lvcreate Udev cookie 0xd4d0b57 (semid 225214464) incremented to 3 libdm-common.c:2575 lvcreate Udev cookie 0xd4d0b57 (semid 225214464) assigned to RESUME task(5) with flags DISABLE_LIBRARY_FALLBACK (0x20) ... activate/fs.c:491 lvcreate Syncing device names libdm-common.c:2360 lvcreate Udev cookie 0xd4d0b57 (semid 225214464) decremented to 2 libdm-common.c:2646 lvcreate Udev cookie 0xd4d0b57 (semid 225214464) waiting for zero """ Since the /dev/dm-x has been created, I don't understand what it waits udev to do? Just waits udev rules to create device symbol links? > lvm2 can be unblocked with 'dmsetup udevcomplete_all' I guess until udev API > will propagate its runtime timeout we can't do much more ATM... Thanks! I remembered there is such a command, but cannot think it up.... > > You can enable full udev debugging to obtain the reasoning which rule was > executed and got frozen. OK. Regards, Eric _______________________________________________ linux-lvm mailing list linux-lvm@redhat.com https://www.redhat.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
