4.9-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit c38f57da428b033f2721b611d84b1f40bde674a8 ]
If a local process has closed a connected socket and hasn't received a RST packet yet, then the socket remains in the table until a timeout expires.
When a vhost_vsock instance is released with the timeout still pending, the socket is never freed because vhost_vsock has already set the SOCK_DONE flag.
Check if the close timer is pending and let it close the socket. This prevents the race which can leak sockets.
Reported-by: Maximilian Riemensberger riemensberger@cadami.net Cc: Graham Whaley graham.whaley@gmail.com Signed-off-by: Stefan Hajnoczi stefanha@redhat.com Signed-off-by: Michael S. Tsirkin mst@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/vhost/vsock.c | 22 +++++++++++++++------- 1 file changed, 15 insertions(+), 7 deletions(-)
diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c index f800f89068db..46f966d7c328 100644 --- a/drivers/vhost/vsock.c +++ b/drivers/vhost/vsock.c @@ -559,13 +559,21 @@ static void vhost_vsock_reset_orphans(struct sock *sk) * executing. */
- if (!vhost_vsock_get(vsk->remote_addr.svm_cid)) { - sock_set_flag(sk, SOCK_DONE); - vsk->peer_shutdown = SHUTDOWN_MASK; - sk->sk_state = SS_UNCONNECTED; - sk->sk_err = ECONNRESET; - sk->sk_error_report(sk); - } + /* If the peer is still valid, no need to reset connection */ + if (vhost_vsock_get(vsk->remote_addr.svm_cid)) + return; + + /* If the close timeout is pending, let it expire. This avoids races + * with the timeout callback. + */ + if (vsk->close_work_scheduled) + return; + + sock_set_flag(sk, SOCK_DONE); + vsk->peer_shutdown = SHUTDOWN_MASK; + sk->sk_state = SS_UNCONNECTED; + sk->sk_err = ECONNRESET; + sk->sk_error_report(sk); }
static int vhost_vsock_dev_release(struct inode *inode, struct file *file)