On Tue, Nov 29, 2016 at 10:46:24PM +0100, Victor Toso wrote: > From: Victor Toso <me@xxxxxxxxxxxxxx> > > Seems that usbredirhost initialization can take longer then > the channel_up call from spice-channel. > > As this seems to be a race, a simple check for NULL pointer should be > enough. Similar fix was done in 5b252b0f499601bcf387c02a4dd35d27ed34c Too many "seems" for my taste in this commit log when this mentions a race condition :( priv->host is initialized in spice_usbredir_channel_set_context() which is called from SpiceUsbDeviceManager::channel_new. SpiceUsbDeviceManager will only start listening for the "channel-new" signal in spice_usb_device_manager_initable_init(). I think what you are suggesting is that spice_usb_device_manager_initable_init() is taking too long, and the usbredir is up and running before we get a chance to set priv->host? NB: channel_up is missing from the backtrace but is what is called between #0 and #1. Can we miss some data if we skip this flushing of pending writes? I guess we cannot have any since priv->host does not exist yet? Christophe > > #0 in usbredirhost_write_guest_data (host=0x0) at usbredirhost.c:876 > #1 in spice_channel_recv_auth (channel=0x55af5f3b8f50 [SpiceUsbredirChannel]) at spice-channel.c:1225 > #2 in spice_channel_coroutine (data=0x55af5f3b8f50) at spice-channel.c:2580 > #3 in coroutine_trampoline (cc=0x55af5f3b85e0) at coroutine_ucontext.c:63 > > Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1399838 > > Signed-off-by: Victor Toso <victortoso@xxxxxxxxxx> > --- > src/channel-usbredir.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/src/channel-usbredir.c b/src/channel-usbredir.c > index 4837d68..561f486 100644 > --- a/src/channel-usbredir.c > +++ b/src/channel-usbredir.c > @@ -817,6 +817,9 @@ static void spice_usbredir_channel_up(SpiceChannel *c) > SpiceUsbredirChannel *channel = SPICE_USBREDIR_CHANNEL(c); > SpiceUsbredirChannelPrivate *priv = channel->priv; > > + if (priv->host == NULL) > + return; > + > /* Flush any pending writes */ > usbredirhost_write_guest_data(priv->host); > } > -- > 2.9.3 > > _______________________________________________ > Spice-devel mailing list > Spice-devel@xxxxxxxxxxxxxxxxxxxxx > https://lists.freedesktop.org/mailman/listinfo/spice-devel
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