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From: Kay Sievers <kay.sievers@vrfy.org>
To: linux-hotplug@vger.kernel.org
Subject: ACTION=="add" in udev rules breaks device naming with the growing
Date: Thu, 30 Oct 2008 16:26:13 +0000	[thread overview]
Message-ID: <1225383973.21973.17.camel@nga.site> (raw)

The current udev rules have some matches on ACTION="add" for a few
device naming instruction. This may break in some circumstances, if the
kernel sends "change" events for the same device.

These events get added to the kernel, to notify about a state change,
which in some cases leads to different symlinks. USB was going to add
"change" event when a device gets reconfigured, which would be
reasonable and nice to have, but it breaks the current device node
naming rule for /dev/bus/usb/. This "change" event can not go in
immediately, but things like this are likely to happen more frequently
in the near future.

To prevent such possible breakage, please get rid of all ACTION="add"
matches which are not exactly meant as such, and remove them entirely,
or change them to ACTION="add|change". People who maintain distro
packages, it would be nice, if you could update currently released, or
just about to be released versions.

You can check for broken rules with:
  udevadm info --export-db > add-event.out
  udevadm trigger --action=change
  udevadm info --export-db > change-event.out
  diff -u add-event.out change-event.out

Any device incorrect device naming differences here should be fixed.

Thanks,
Kay


                 reply	other threads:[~2008-10-30 16:26 UTC|newest]

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