[Qemu-devel] [PATCH 1/1] net: fix queue's purge on VM stop

[Thibaut Collet]

For netdev backend with no receive callback, packets must not be enqueued. When
VM stops the enqueued packets are purged (see fixes ca77d85e1dbf). That causes a
qemu segfault due to a call of a NULL pointer function.

Function to create net client is modified to allow backend to specify the size
of the queue.
For netdev backend with no receive callback, the queue size is set to 0 to
prevent enqueuing of packets.
For other netdev backend, a default queue size is provided. This value (set to
10000) is the value previously set to any queue.

Signed-off-by: Thibaut Collet <address@hidden>
---
 include/net/net.h   |    3 ++-
 include/net/queue.h |    5 ++++-
 net/dump.c          |    3 ++-
 net/hub.c           |    3 ++-
 net/l2tpv3.c        |    3 ++-
 net/net.c           |   10 ++++++----
 net/netmap.c        |    3 ++-
 net/queue.c         |    4 ++--
 net/slirp.c         |    3 ++-
 net/socket.c        |    9 ++++++---
 net/tap-win32.c     |    3 ++-
 net/tap.c           |    3 ++-
 net/vde.c           |    3 ++-
 net/vhost-user.c    |    4 +++-
 14 files changed, 39 insertions(+), 20 deletions(-)

diff --git a/include/net/net.h b/include/net/net.h
index e66ca03..cb3e2df 100644
--- a/include/net/net.h
+++ b/include/net/net.h
@@ -104,7 +104,8 @@ int qemu_find_net_clients_except(const char *id, 
NetClientState **ncs,
 NetClientState *qemu_new_net_client(NetClientInfo *info,
                                     NetClientState *peer,
                                     const char *model,
-                                    const char *name);
+                                    const char *name,
+                                    uint32_t queue_size);
 NICState *qemu_new_nic(NetClientInfo *info,
                        NICConf *conf,
                        const char *model,
diff --git a/include/net/queue.h b/include/net/queue.h
index fc02b33..4659c5a 100644
--- a/include/net/queue.h
+++ b/include/net/queue.h
@@ -34,7 +34,10 @@ typedef void (NetPacketSent) (NetClientState *sender, 
ssize_t ret);
 #define QEMU_NET_PACKET_FLAG_NONE  0
 #define QEMU_NET_PACKET_FLAG_RAW  (1<<0)
 
-NetQueue *qemu_new_net_queue(void *opaque);
+#define QEMU_DEFAULT_QUEUE_SIZE  10000
+#define QEMU_EMPTY_QUEUE         0
+
+NetQueue *qemu_new_net_queue(void *opaque, uint32_t queue_size);
 
 void qemu_del_net_queue(NetQueue *queue);
 
diff --git a/net/dump.c b/net/dump.c
index 9d3a09e..299b09e 100644
--- a/net/dump.c
+++ b/net/dump.c
@@ -129,7 +129,8 @@ static int net_dump_init(NetClientState *peer, const char 
*device,
         return -1;
     }
 
-    nc = qemu_new_net_client(&net_dump_info, peer, device, name);
+    nc = qemu_new_net_client(&net_dump_info, peer, device, name,
+                             QEMU_DEFAULT_QUEUE_SIZE);
 
     snprintf(nc->info_str, sizeof(nc->info_str),
              "dump to %s (len=%d)", filename, len);
diff --git a/net/hub.c b/net/hub.c
index 2b60ab9..a42cac3 100644
--- a/net/hub.c
+++ b/net/hub.c
@@ -151,7 +151,8 @@ static NetHubPort *net_hub_port_new(NetHub *hub, const char 
*name)
         name = default_name;
     }
 
-    nc = qemu_new_net_client(&net_hub_port_info, NULL, "hub", name);
+    nc = qemu_new_net_client(&net_hub_port_info, NULL, "hub", name,
+                             QEMU_DEFAULT_QUEUE_SIZE);
     port = DO_UPCAST(NetHubPort, nc, nc);
     port->id = id;
     port->hub = hub;
diff --git a/net/l2tpv3.c b/net/l2tpv3.c
index 8c598b0..1d2e4e5 100644
--- a/net/l2tpv3.c
+++ b/net/l2tpv3.c
@@ -548,7 +548,8 @@ int net_init_l2tpv3(const NetClientOptions *opts,
     struct addrinfo *result = NULL;
     char *srcport, *dstport;
 
-    nc = qemu_new_net_client(&net_l2tpv3_info, peer, "l2tpv3", name);
+    nc = qemu_new_net_client(&net_l2tpv3_info, peer, "l2tpv3", name,
+                             QEMU_DEFAULT_QUEUE_SIZE);
 
     s = DO_UPCAST(NetL2TPV3State, nc, nc);
 
diff --git a/net/net.c b/net/net.c
index 7427f6a..bcf69da 100644
--- a/net/net.c
+++ b/net/net.c
@@ -214,6 +214,7 @@ static void qemu_net_client_setup(NetClientState *nc,
                                   NetClientState *peer,
                                   const char *model,
                                   const char *name,
+                                  uint32_t queue_size,
                                   NetClientDestructor *destructor)
 {
     nc->info = info;
@@ -231,21 +232,22 @@ static void qemu_net_client_setup(NetClientState *nc,
     }
     QTAILQ_INSERT_TAIL(&net_clients, nc, next);
 
-    nc->incoming_queue = qemu_new_net_queue(nc);
+    nc->incoming_queue = qemu_new_net_queue(nc, queue_size);
     nc->destructor = destructor;
 }
 
 NetClientState *qemu_new_net_client(NetClientInfo *info,
                                     NetClientState *peer,
                                     const char *model,
-                                    const char *name)
+                                    const char *name,
+                                    uint32_t queue_size)
 {
     NetClientState *nc;
 
     assert(info->size >= sizeof(NetClientState));
 
     nc = g_malloc0(info->size);
-    qemu_net_client_setup(nc, info, peer, model, name,
+    qemu_net_client_setup(nc, info, peer, model, name, queue_size,
                           qemu_net_client_destructor);
 
     return nc;
@@ -271,7 +273,7 @@ NICState *qemu_new_nic(NetClientInfo *info,
 
     for (i = 0; i < queues; i++) {
         qemu_net_client_setup(&nic->ncs[i], info, peers[i], model, name,
-                              NULL);
+                              QEMU_DEFAULT_QUEUE_SIZE, NULL);
         nic->ncs[i].queue_index = i;
     }
 
diff --git a/net/netmap.c b/net/netmap.c
index 0c1772b..3ddfc8e 100644
--- a/net/netmap.c
+++ b/net/netmap.c
@@ -461,7 +461,8 @@ int net_init_netmap(const NetClientOptions *opts,
         return -1;
     }
     /* Create the object. */
-    nc = qemu_new_net_client(&net_netmap_info, peer, "netmap", name);
+    nc = qemu_new_net_client(&net_netmap_info, peer, "netmap", name,
+                             QEMU_DEFAULT_QUEUE_SIZE);
     s = DO_UPCAST(NetmapState, nc, nc);
     s->me = me;
     s->vnet_hdr_len = 0;
diff --git a/net/queue.c b/net/queue.c
index ebbe2bb..d6ddda5 100644
--- a/net/queue.c
+++ b/net/queue.c
@@ -58,14 +58,14 @@ struct NetQueue {
     unsigned delivering : 1;
 };
 
-NetQueue *qemu_new_net_queue(void *opaque)
+NetQueue *qemu_new_net_queue(void *opaque, uint32_t queue_size)
 {
     NetQueue *queue;
 
     queue = g_new0(NetQueue, 1);
 
     queue->opaque = opaque;
-    queue->nq_maxlen = 10000;
+    queue->nq_maxlen = queue_size;
     queue->nq_count = 0;
 
     QTAILQ_INIT(&queue->packets);
diff --git a/net/slirp.c b/net/slirp.c
index 9bbed74..c91e929 100644
--- a/net/slirp.c
+++ b/net/slirp.c
@@ -234,7 +234,8 @@ static int net_slirp_init(NetClientState *peer, const char 
*model,
     }
 #endif
 
-    nc = qemu_new_net_client(&net_slirp_info, peer, model, name);
+    nc = qemu_new_net_client(&net_slirp_info, peer, model, name,
+                             QEMU_DEFAULT_QUEUE_SIZE);
 
     snprintf(nc->info_str, sizeof(nc->info_str),
              "net=%s,restrict=%s", inet_ntoa(net),
diff --git a/net/socket.c b/net/socket.c
index c30e03f..d5c718c 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -387,7 +387,8 @@ static NetSocketState 
*net_socket_fd_init_dgram(NetClientState *peer,
         }
     }
 
-    nc = qemu_new_net_client(&net_dgram_socket_info, peer, model, name);
+    nc = qemu_new_net_client(&net_dgram_socket_info, peer, model, name,
+                             QEMU_DEFAULT_QUEUE_SIZE);
 
     s = DO_UPCAST(NetSocketState, nc, nc);
 
@@ -436,7 +437,8 @@ static NetSocketState 
*net_socket_fd_init_stream(NetClientState *peer,
     NetClientState *nc;
     NetSocketState *s;
 
-    nc = qemu_new_net_client(&net_socket_info, peer, model, name);
+    nc = qemu_new_net_client(&net_socket_info, peer, model, name,
+                             QEMU_DEFAULT_QUEUE_SIZE);
 
     snprintf(nc->info_str, sizeof(nc->info_str), "socket: fd=%d", fd);
 
@@ -543,7 +545,8 @@ static int net_socket_listen_init(NetClientState *peer,
         return -1;
     }
 
-    nc = qemu_new_net_client(&net_socket_info, peer, model, name);
+    nc = qemu_new_net_client(&net_socket_info, peer, model, name,
+                             QEMU_DEFAULT_QUEUE_SIZE);
     s = DO_UPCAST(NetSocketState, nc, nc);
     s->fd = -1;
     s->listen_fd = fd;
diff --git a/net/tap-win32.c b/net/tap-win32.c
index 8aee611..dd6046a 100644
--- a/net/tap-win32.c
+++ b/net/tap-win32.c
@@ -737,7 +737,8 @@ static int tap_win32_init(NetClientState *peer, const char 
*model,
         return -1;
     }
 
-    nc = qemu_new_net_client(&net_tap_win32_info, peer, model, name);
+    nc = qemu_new_net_client(&net_tap_win32_info, peer, model, name,
+                             QEMU_DEFAULT_QUEUE_SIZE);
 
     s = DO_UPCAST(TAPState, nc, nc);
 
diff --git a/net/tap.c b/net/tap.c
index 968df46..383d3ad 100644
--- a/net/tap.c
+++ b/net/tap.c
@@ -346,7 +346,8 @@ static TAPState *net_tap_fd_init(NetClientState *peer,
     NetClientState *nc;
     TAPState *s;
 
-    nc = qemu_new_net_client(&net_tap_info, peer, model, name);
+    nc = qemu_new_net_client(&net_tap_info, peer, model, name,
+                             QEMU_DEFAULT_QUEUE_SIZE);
 
     s = DO_UPCAST(TAPState, nc, nc);
 
diff --git a/net/vde.c b/net/vde.c
index 2a619fb..b6d28cf 100644
--- a/net/vde.c
+++ b/net/vde.c
@@ -95,7 +95,8 @@ static int net_vde_init(NetClientState *peer, const char 
*model,
         return -1;
     }
 
-    nc = qemu_new_net_client(&net_vde_info, peer, model, name);
+    nc = qemu_new_net_client(&net_vde_info, peer, model, name,
+                             QEMU_DEFAULT_QUEUE_SIZE);
 
     snprintf(nc->info_str, sizeof(nc->info_str), "sock=%s,fd=%d",
              sock, vde_datafd(vde));
diff --git a/net/vhost-user.c b/net/vhost-user.c
index 1d86a2b..71f8758 100644
--- a/net/vhost-user.c
+++ b/net/vhost-user.c
@@ -137,7 +137,9 @@ static int net_vhost_user_init(NetClientState *peer, const 
char *device,
     NetClientState *nc;
     VhostUserState *s;
 
-    nc = qemu_new_net_client(&net_vhost_user_info, peer, device, name);
+    /* We don't provide a valid queue: no receive callback */
+    nc = qemu_new_net_client(&net_vhost_user_info, peer, device, name,
+                             QEMU_EMPTY_QUEUE);
 
     snprintf(nc->info_str, sizeof(nc->info_str), "vhost-user to %s",
              chr->label);
-- 
1.7.10.4