tree 4d753b6aa3cb50f68f15e85b02cc7f17a443c802
parent d0fe8c888b1fd1a2f84b9962cabcb98a70988aec
author Nikolay Aleksandrov <nikolay@redhat.com> 1379595756 +0200
committer David S. Miller <davem@davemloft.net> 1379614553 -0400

netconsole: fix a deadlock with rtnl and netconsole's mutex

This bug was introduced by commit
7a163bfb7ce50895bbe67300ea610d31b9c09230 ("netconsole: avoid a crash with
multiple sysfs writers"). In store_enabled() we have the following
sequence: acquire nt->mutex then rtnl, but in the netconsole netdev
notifier we have rtnl then nt->mutex effectively leading to a deadlock.
The NULL pointer dereference that the above commit tries to fix is
actually due to another bug in netpoll_cleanup(). This is fixed by dropping
the mutex from the netdev notifier as it's already protected by rtnl.

Signed-off-by: Nikolay Aleksandrov <nikolay@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>