diff options
| author | NeilBrown <neilb@suse.de> | 2006-10-20 11:52:44 +1000 |
|---|---|---|
| committer | Chris Wright <chrisw@sous-sol.org> | 2006-11-03 17:33:47 -0800 |
| commit | 02bb8f3f912d8a2048ed7502a733f64c6bf8fcfe (patch) | |
| tree | 9f164d0e41380c9ed42849c6639bf9c2b4bb3d6d /net | |
| parent | 8fb3dd17ba82cf264224fc19c69efb42e4370f28 (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>
Diffstat (limited to 'net')
| -rw-r--r-- | net/sunrpc/svcsock.c | 2 |
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; |