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| author | Eric Dumazet <edumazet@google.com> | 2012-06-05 07:00:18 +0400 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2012-06-06 21:45:15 +0400 |
| commit | 55432d2b543a4b6dfae54f5c432a566877a85d90 (patch) | |
| tree | f830eb5150e38be149fcfce74f68716f5bf2641a | |
| parent | dd03cff23d694cfb0fdae80cb618e7ced05ea696 (diff) | |
| download | linux-55432d2b543a4b6dfae54f5c432a566877a85d90.tar.xz | |
inetpeer: fix a race in inetpeer_gc_worker()
commit 5faa5df1fa2024 (inetpeer: Invalidate the inetpeer tree along with
the routing cache) added a race :
Before freeing an inetpeer, we must respect a RCU grace period, and make
sure no user will attempt to increase refcnt.
inetpeer_invalidate_tree() waits for a RCU grace period before inserting
inetpeer tree into gc_list and waking the worker. At that time, no
concurrent lookup can find a inetpeer in this tree.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Acked-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | include/net/inetpeer.h | 5 | ||||
| -rw-r--r-- | net/ipv4/inetpeer.c | 16 |
2 files changed, 16 insertions, 5 deletions
diff --git a/include/net/inetpeer.h b/include/net/inetpeer.h index b94765e38e80..2040bff945d4 100644 --- a/include/net/inetpeer.h +++ b/include/net/inetpeer.h @@ -40,7 +40,10 @@ struct inet_peer { u32 pmtu_orig; u32 pmtu_learned; struct inetpeer_addr_base redirect_learned; - struct list_head gc_list; + union { + struct list_head gc_list; + struct rcu_head gc_rcu; + }; /* * Once inet_peer is queued for deletion (refcnt == -1), following fields * are not available: rid, ip_id_count, tcp_ts, tcp_ts_stamp diff --git a/net/ipv4/inetpeer.c b/net/ipv4/inetpeer.c index d4d61b694fab..dfba343b2509 100644 --- a/net/ipv4/inetpeer.c +++ b/net/ipv4/inetpeer.c @@ -560,6 +560,17 @@ bool inet_peer_xrlim_allow(struct inet_peer *peer, int timeout) } EXPORT_SYMBOL(inet_peer_xrlim_allow); +static void inetpeer_inval_rcu(struct rcu_head *head) +{ + struct inet_peer *p = container_of(head, struct inet_peer, gc_rcu); + + spin_lock_bh(&gc_lock); + list_add_tail(&p->gc_list, &gc_list); + spin_unlock_bh(&gc_lock); + + schedule_delayed_work(&gc_work, gc_delay); +} + void inetpeer_invalidate_tree(int family) { struct inet_peer *old, *new, *prev; @@ -576,10 +587,7 @@ void inetpeer_invalidate_tree(int family) prev = cmpxchg(&base->root, old, new); if (prev == old) { base->total = 0; - spin_lock(&gc_lock); - list_add_tail(&prev->gc_list, &gc_list); - spin_unlock(&gc_lock); - schedule_delayed_work(&gc_work, gc_delay); + call_rcu(&prev->gc_rcu, inetpeer_inval_rcu); } out: |