On 04/27/2018 05:19 PM, xiangxia.m....@gmail.com wrote:
From: Tonghao Zhang <xiangxia.m....@gmail.com>
When qemu close the unix socket fd of the vhostuser as a
server, and then immediately delete the vhostuser port on
openvswitch. There will be a deadlock.
A thread (fdset event thread): B thread:
1. fdset_event_dispatch rte_vhost_driver_unregister
2. set the fd busy to 1. lock vsocket->conn_mutex
3. vhost_user_read_cb fdset_del waits busy changed to 0.
4. vhost peer closed, remove the
conn from vsocket->conn_list:
lock vsocket->conn_mutex
5. set the fd busy to 0
Fixes: 65388b43 ("vhost: fix fd leaks for vhost-user server mode")
Cc: sta...@dpdk.org
Cc: Yuanhan Liu <y...@fridaylinux.org>
Signed-off-by: Tonghao Zhang <xiangxia.m....@gmail.com>
---
lib/librte_vhost/fd_man.c | 32 ++++++++++++++++++++++++++++++++
lib/librte_vhost/fd_man.h | 1 +
lib/librte_vhost/socket.c | 13 ++++++++++++-
3 files changed, 45 insertions(+), 1 deletion(-)
diff --git a/lib/librte_vhost/fd_man.c b/lib/librte_vhost/fd_man.c
index 8590ee5..b24c27d 100644
--- a/lib/librte_vhost/fd_man.c
+++ b/lib/librte_vhost/fd_man.c
@@ -174,6 +174,38 @@
return dat;
}
+/**
+ * Unregister the fd from the fdset.
+ *
+ * If parameters are invalid, return directly -2.
+ * And check whether fd is busy, if yes, return -1.
+ * Otherwise, try to delete the fd from fdset and
+ * return true.
+ */
+int
+fdset_try_del(struct fdset *pfdset, int fd)
+{
+ int i;
+
+ if (pfdset == NULL || fd == -1)
+ return -2;
+
+ pthread_mutex_lock(&pfdset->fd_mutex);
+ i = fdset_find_fd(pfdset, fd);
+ if (i != -1 && pfdset->fd[i].busy) {
+ pthread_mutex_unlock(&pfdset->fd_mutex);
+ return -1;
+ }
+
+ if (i != -1) {
+ pfdset->fd[i].fd = -1;
+ pfdset->fd[i].rcb = pfdset->fd[i].wcb = NULL;
+ pfdset->fd[i].dat = NULL;
+ }
+
+ pthread_mutex_unlock(&pfdset->fd_mutex);
+ return 0;
+}
/**
* This functions runs in infinite blocking loop until there is no fd in
diff --git a/lib/librte_vhost/fd_man.h b/lib/librte_vhost/fd_man.h
index 76a42fb..3331bcd 100644
--- a/lib/librte_vhost/fd_man.h
+++ b/lib/librte_vhost/fd_man.h
@@ -44,6 +44,7 @@ int fdset_add(struct fdset *pfdset, int fd,
fd_cb rcb, fd_cb wcb, void *dat);
void *fdset_del(struct fdset *pfdset, int fd);
+int fdset_try_del(struct fdset *pfdset, int fd);
void *fdset_event_dispatch(void *arg);
diff --git a/lib/librte_vhost/socket.c b/lib/librte_vhost/socket.c
index 4a561ad..822db41 100644
--- a/lib/librte_vhost/socket.c
+++ b/lib/librte_vhost/socket.c
@@ -922,13 +922,24 @@ struct vhost_user_reconnect_list {
vhost_user_remove_reconnect(vsocket);
}
+again:
pthread_mutex_lock(&vsocket->conn_mutex);
for (conn = TAILQ_FIRST(&vsocket->conn_list);
conn != NULL;
conn = next) {
next = TAILQ_NEXT(conn, next);
- fdset_del(&vhost_user.fdset, conn->connfd);
+ /*
+ * If r/wcb is executing, release the
+ * conn_mutex lock, and try again since
+ * the r/wcb may use the conn_mutex lock.
+ */
+ if (fdset_try_del(&vhost_user.fdset,
+ conn->connfd) == -1) {
+
pthread_mutex_unlock(&vsocket->conn_mutex);
+ goto again;
+ }
+
RTE_LOG(INFO, VHOST_CONFIG,
"free connfd = %d for device '%s'\n",
conn->connfd, path);
It looks a bit fragile at first, but I don't have a better alternative
in mind, so:
Acked-by: Maxime Coquelin <maxime.coque...@redhat.com>
Thanks,
Maxime
