Messages in this thread Patch in this message | | | From | Andi Kleen <> | Subject | [PATCH] [31/139] llc: fix a device refcount imbalance | Date | Tue, 1 Feb 2011 16:43:46 -0800 (PST) |
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2.6.35-longterm review patch. If anyone has any objections, please let me know.
------------------ From: Eric Dumazet <eric.dumazet@gmail.com>
commit 35d9b0c906ad92d32a0b8db5daa6fabfcc2f068d upstream.
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> Signed-off-by: Andi Kleen <ak@linux.intel.com> Cc: Octavian Purdila <opurdila@ixiacom.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- net/llc/af_llc.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
Index: linux-2.6.35.y/net/llc/af_llc.c =================================================================== --- linux-2.6.35.y.orig/net/llc/af_llc.c +++ linux-2.6.35.y/net/llc/af_llc.c @@ -317,8 +317,9 @@ static int llc_ui_bind(struct socket *so 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 *so !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; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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