From 53488f0275d6c8a121af49f7ac817d09ce68090d Mon Sep 17 00:00:00 2001 From: David Gibson Date: Fri, 5 Jul 2013 17:11:46 +1000 Subject: Use RING_FOREACH_SAFE in red_channel.c functions which are missing it Currently, both red_channel_pipes_add_type() and red_channel_pipes_add_empty_msg() use plaing RING_FOREACH() which is not safe versus removals from the ring within the loop body. Although it's rare, such a removal can occur in both cases. In the case of red_channel_pipes_add_type() we have: red_channel_pipes_add_type() -> red_channel_client_pipe_add_type() -> red_channel_client_push() And in the case of red_channel_client_pipes_add_empty_msg() we have: red_channel_client_pipes_add_empty_msg() -> red_channel_client_pipe_add_empty_msg() -> red_channel_client_push() But red_channel_client_push() can cause a removal from the clients ring if a network error occurs: red_channel_client_push() -> red_channel_client_send() -> red_peer_handle_outgoing() -> handler->cb->on_error callback = red_channel_client_default_peer_on_error() -> red_channel_client_disconnect() -> red_channel_remove_client() -> ring_remove() When this error path does occur, the assertion in RING_FOREACH()'s ring_next() trips, and the process containing the spice server is aborted. i.e. your whole VM dies, as a result of an unfortunately timed network error on the spice channel. Please apply. Signed-off-by: David Gibson --- server/red_channel.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/server/red_channel.c b/server/red_channel.c index c0b17819..8742008d 100644 --- a/server/red_channel.c +++ b/server/red_channel.c @@ -1572,9 +1572,9 @@ void red_channel_client_pipe_add_type(RedChannelClient *rcc, int pipe_item_type) void red_channel_pipes_add_type(RedChannel *channel, int pipe_item_type) { - RingItem *link; + RingItem *link, *next; - RING_FOREACH(link, &channel->clients) { + RING_FOREACH_SAFE(link, next, &channel->clients) { red_channel_client_pipe_add_type( SPICE_CONTAINEROF(link, RedChannelClient, channel_link), pipe_item_type); @@ -1593,9 +1593,9 @@ void red_channel_client_pipe_add_empty_msg(RedChannelClient *rcc, int msg_type) void red_channel_pipes_add_empty_msg(RedChannel *channel, int msg_type) { - RingItem *link; + RingItem *link, *next; - RING_FOREACH(link, &channel->clients) { + RING_FOREACH_SAFE(link, next, &channel->clients) { red_channel_client_pipe_add_empty_msg( SPICE_CONTAINEROF(link, RedChannelClient, channel_link), msg_type); -- cgit