summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorNeilBrown <neilb@suse.de>2006-10-20 11:52:44 +1000
committerChris Wright <chrisw@sous-sol.org>2006-11-03 17:33:47 -0800
commit02bb8f3f912d8a2048ed7502a733f64c6bf8fcfe (patch)
tree9f164d0e41380c9ed42849c6639bf9c2b4bb3d6d
parent8fb3dd17ba82cf264224fc19c69efb42e4370f28 (diff)
[PATCH] knfsd: Fix race that can disable NFS server.
This is a long standing bug that seems to have only recently become apparent, presumably due to increasing use of NFS over TCP - many distros seem to be making it the default. The SK_CONN bit gets set when a listening socket may be ready for an accept, just as SK_DATA is set when data may be available. It is entirely possible for svc_tcp_accept to be called with neither of these set. It doesn't happen often but there is a small race in svc_sock_enqueue as SK_CONN and SK_DATA are tested outside the spin_lock. They could be cleared immediately after the test and before the lock is gained. This normally shouldn't be a problem. The sockets are non-blocking so trying to read() or accept() when ther is nothing to do is not a problem. However: svc_tcp_recvfrom makes the decision "Should I accept() or should I read()" based on whether SK_CONN is set or not. This usually works but is not safe. The decision should be based on whether it is a TCP_LISTEN socket or a TCP_CONNECTED socket. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: Chris Wright <chrisw@sous-sol.org>
-rw-r--r--net/sunrpc/svcsock.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index d9a95732df46..2544acdbe119 100644
--- a/net/sunrpc/svcsock.c
+++ b/net/sunrpc/svcsock.c
@@ -902,7 +902,7 @@ svc_tcp_recvfrom(struct svc_rqst *rqstp)
return 0;
}
- if (test_bit(SK_CONN, &svsk->sk_flags)) {
+ if (svsk->sk_sk->sk_state == TCP_LISTEN) {
svc_tcp_accept(svsk);
svc_sock_received(svsk);
return 0;