diff options
| author | Eric Dumazet <eric.dumazet@gmail.com> | 2010-12-05 02:03:26 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2010-12-08 09:58:44 -0800 |
| commit | 35d9b0c906ad92d32a0b8db5daa6fabfcc2f068d (patch) | |
| tree | d9cdc72902f327ff377dd8bedfaeb0a8eead24a5 | |
| parent | 75c1c82566f23dd539fb7ccbf57a1caa7ba82628 (diff) | |
llc: fix a device refcount imbalance
Le dimanche 05 décembre 2010 à 12:23 +0100, Eric Dumazet a écrit :
> Le dimanche 05 décembre 2010 à 09:19 +0100, Eric Dumazet a écrit :
>
> > Hmm..
> >
> > If somebody can explain why RTNL is held in arp_ioctl() (and therefore
> > in arp_req_delete()), we might first remove RTNL use in arp_ioctl() so
> > that your patch can be applied.
> >
> > Right now it is not good, because RTNL wont be necessarly held when you
> > are going to call arp_invalidate() ?
>
> While doing this analysis, I found a refcount bug in llc, I'll send a
> patch for net-2.6
Oh well, of course I must first fix the bug in net-2.6, and wait David
pull the fix in net-next-2.6 before sending this rcu conversion.
Note: this patch should be sent to stable teams (2.6.34 and up)
[PATCH net-2.6] llc: fix a device refcount imbalance
commit abf9d537fea225 (llc: add support for SO_BINDTODEVICE) added one
refcount imbalance in llc_ui_bind(), because dev_getbyhwaddr() doesnt
take a reference on device, while dev_get_by_index() does.
Fix this using RCU locking. And since an RCU conversion will be done for
2.6.38 for dev_getbyhwaddr(), put the rcu_read_lock/unlock exactly at
their final place.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: stable@kernel.org
Cc: Octavian Purdila <opurdila@ixiacom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/llc/af_llc.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/net/llc/af_llc.c b/net/llc/af_llc.c index 582612998211..e35dbe55f520 100644 --- a/net/llc/af_llc.c +++ b/net/llc/af_llc.c @@ -317,8 +317,9 @@ static int llc_ui_bind(struct socket *sock, struct sockaddr *uaddr, int addrlen) goto out; rc = -ENODEV; rtnl_lock(); + rcu_read_lock(); if (sk->sk_bound_dev_if) { - llc->dev = dev_get_by_index(&init_net, sk->sk_bound_dev_if); + llc->dev = dev_get_by_index_rcu(&init_net, sk->sk_bound_dev_if); if (llc->dev) { if (!addr->sllc_arphrd) addr->sllc_arphrd = llc->dev->type; @@ -329,13 +330,13 @@ static int llc_ui_bind(struct socket *sock, struct sockaddr *uaddr, int addrlen) !llc_mac_match(addr->sllc_mac, llc->dev->dev_addr)) { rc = -EINVAL; - dev_put(llc->dev); llc->dev = NULL; } } } else llc->dev = dev_getbyhwaddr(&init_net, addr->sllc_arphrd, addr->sllc_mac); + rcu_read_unlock(); rtnl_unlock(); if (!llc->dev) goto out; |