[2.6.20.17 review 08/58] Netpoll leak

[Willy Tarreau <w@1wt.eu>]

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[NETPOLL]: Fix a leak-n-bug in netpoll_cleanup()

93ec2c723e3f8a216dde2899aeb85c648672bc6b applied excessive duct tape to
the netpoll beast's netpoll_cleanup(), thus substituting one leak with
another, and opening up a little buglet :-)

net_device->npinfo (netpoll_info) is a shared and refcounted object and
cannot simply be set NULL the first time netpoll_cleanup() is called.
Otherwise, further netpoll_cleanup()'s see np->dev->npinfo == NULL and
become no-ops, thus leaking. And it's a bug too: the first call to
netpoll_cleanup() would thus (annoyingly) "disable" other (still alive)
netpolls too. Maybe nobody noticed this because netconsole (only user
of netpoll) never supported multiple netpoll objects earlier.

This is a trivial and obvious one-line fixlet.

Signed-off-by: Satyam Sharma <ssatyam@cse.iitk.ac.in>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Willy Tarreau <w@1wt.eu>
---
 net/core/netpoll.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index 522e441..3431d48 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -776,7 +776,6 @@ void netpoll_cleanup(struct netpoll *np)
 				spin_unlock_irqrestore(&npinfo->rx_lock, flags);
 			}
 
-			np->dev->npinfo = NULL;
 			if (atomic_dec_and_test(&npinfo->refcnt)) {
 				skb_queue_purge(&npinfo->arp_tx);
  				skb_queue_purge(&npinfo->txq);
@@ -784,6 +783,7 @@ void netpoll_cleanup(struct netpoll *np)
  				flush_scheduled_work();
 
 				kfree(npinfo);
+				np->dev->npinfo = NULL;
 			}
 		}
 
-- 
1.5.2.5

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