[dpdk-dev] [PATCH v4] vhost: fix crash on port deletion
From: Gaoxiang Liu <hidden>
Date: 2021-08-18 16:09:21
Subsystem:
library code, the rest · Maintainers:
Andrew Morton, Linus Torvalds
The rte_vhost_driver_unregister() and vhost_user_server_new_connection()
can be called at the same time by 2 threads.
Eg thread1 calls rte_vhost_driver_unregister() and frees the memory of
conn_list.
"vhost-events" thread calls fdset_event_dispatch,
then calls vhost_user_server_new_connection().
A new conn fd is added in fdset in vhost_user_server_new_connection(),
then "vhost-events" thread calls vhost_user_read_cb().
when thread1 frees the memory of vsocket, vhost_user_read_cb()
will access invalid memory of socket.
When vhostuser port is created as a client, the issue also exists.
The fix is to move the "fdset_try_del" in front of free memory of conn,
then avoid the race condition.
The core trace is:
Program terminated with signal 11, Segmentation fault.
Fixes: 52d874dc6705 ("vhost: fix crash on closing in client mode")
Signed-off-by: Gaoxiang Liu <redacted>
v2:
* Fix coding style issues
v3:
* Add detailed log
v4:
* Add the reason, when vhostuser port is created as a server.
---
lib/vhost/socket.c | 27 ++++++++++++++-------------
1 file changed, 14 insertions(+), 13 deletions(-)
diff --git a/lib/vhost/socket.c b/lib/vhost/socket.c
index 5d0d728d5..2eb8fcadd 100644
--- a/lib/vhost/socket.c
+++ b/lib/vhost/socket.c@@ -1024,6 +1024,20 @@ rte_vhost_driver_unregister(const char *path) for (i = 0; i < vhost_user.vsocket_cnt; i++) { struct vhost_user_socket *vsocket = vhost_user.vsockets[i]; + if (vsocket->is_server) { + /* + * If r/wcb is executing, release vhost_user's + * mutex lock, and try again since the r/wcb + * may use the mutex lock. + */ + if (fdset_try_del(&vhost_user.fdset, vsocket->socket_fd) == -1) { + pthread_mutex_unlock(&vhost_user.mutex); + goto again; + } + } else if (vsocket->reconnect) { + vhost_user_remove_reconnect(vsocket); + } + if (!strcmp(vsocket->path, path)) { pthread_mutex_lock(&vsocket->conn_mutex); for (conn = TAILQ_FIRST(&vsocket->conn_list);
@@ -1056,21 +1070,8 @@ rte_vhost_driver_unregister(const char *path) pthread_mutex_unlock(&vsocket->conn_mutex); if (vsocket->is_server) { - /* - * If r/wcb is executing, release vhost_user's - * mutex lock, and try again since the r/wcb - * may use the mutex lock. - */ - if (fdset_try_del(&vhost_user.fdset, - vsocket->socket_fd) == -1) { - pthread_mutex_unlock(&vhost_user.mutex); - goto again; - } - close(vsocket->socket_fd); unlink(path); - } else if (vsocket->reconnect) { - vhost_user_remove_reconnect(vsocket); } pthread_mutex_destroy(&vsocket->conn_mutex);
--
2.32.0