diff options
| author | Nikolay Aleksandrov <nikolay@redhat.com> | 2013-09-19 15:02:35 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-10-13 14:51:07 -0700 |
| commit | f6f88d6f41938e39971a5c0fce3aa8d26d3dd9de (patch) | |
| tree | dbf36ef28dc8806b3f788cfa7267892bf8232121 | |
| parent | 63195262c5555dc90fde66d1be41ab102cf00adb (diff) | |
netpoll: fix NULL pointer dereference in netpoll_cleanup
[ Upstream commit d0fe8c888b1fd1a2f84b9962cabcb98a70988aec ]
I've been hitting a NULL ptr deref while using netconsole because the
np->dev check and the pointer manipulation in netpoll_cleanup are done
without rtnl and the following sequence happens when having a netconsole
over a vlan and we remove the vlan while disabling the netconsole:
CPU 1 CPU2
removes vlan and calls the notifier
enters store_enabled(), calls
netdev_cleanup which checks np->dev
and then waits for rtnl
executes the netconsole netdev
release notifier making np->dev
== NULL and releases rtnl
continues to dereference a member of
np->dev which at this point is == NULL
Signed-off-by: Nikolay Aleksandrov <nikolay@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | net/core/netpoll.c | 9 |
1 files changed, 4 insertions, 5 deletions
diff --git a/net/core/netpoll.c b/net/core/netpoll.c index 207a178f73b..c4971372340 100644 --- a/net/core/netpoll.c +++ b/net/core/netpoll.c @@ -927,15 +927,14 @@ EXPORT_SYMBOL_GPL(__netpoll_cleanup); void netpoll_cleanup(struct netpoll *np) { - if (!np->dev) - return; - rtnl_lock(); + if (!np->dev) + goto out; __netpoll_cleanup(np); - rtnl_unlock(); - dev_put(np->dev); np->dev = NULL; +out: + rtnl_unlock(); } EXPORT_SYMBOL(netpoll_cleanup); |