diff options
| author | Nikolay Aleksandrov <nikolay@redhat.com> | 2013-09-19 15:02:35 +0200 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2013-10-26 21:06:08 +0100 |
| commit | 2eb90b30797b3c908b597e4a2a700d6ef9ae0196 (patch) | |
| tree | 09e141d0c5795c264cdfce3f165aac29db34d9f4 /net/core | |
| parent | 836f6cb46716e36cb8d31a402c6661af5c895135 (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: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'net/core')
| -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 db4bb7a9ca78..9649cead0028 100644 --- a/net/core/netpoll.c +++ b/net/core/netpoll.c @@ -923,15 +923,14 @@ 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); |