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On Mon, Jan 28, 2019 at 10:29 AM Jakub Janku <jja...@redhat.com> wrote: > > Hi, > > I tried to fix this bug in a less radical way, but my patch unfortunately did > not cover all the cases. > > I obtained some logs from James Harvey which make the situation clearer - it > can be found here: > https://termbin.com/40un > So I'll try to explain what's happening: > > James uses KDE which has a clipboard manager integrated in (klipper). > > (1) user copies something in the guest, grab is sent to the spice-gtk > (2) clipboard manager immediately requests the data, data is retrieved from > the vdagent > (3) user pastes the copied data in guest, this causes a quick re-grab in the > guest = a clipboard release message is sent to spice-gtk and it is > immediately followed by a new grab > (4) spice-gtk receives clipboard release, so it clears the clipboard > (5) clipboard manager detects that the clipboard has no owner, so it grabs it > itself, advertising the data it originally obtained from us in step (2) (this > normally enables the user to paste the data even after the source app has > been closed) > (6) spice-gtk receives "owner-change" signal caused by the grab in step (5), > requests clipboard targets and sends a grab to vdagent > (7) spice-gtk finally receives the grab from step (3), so it sets the > clipboard using gtk_clipboard_set_with_owner() > (8) vdagent receives grab from step (6), so it too sets the clipboard using > gtk_clipboard_set_with_owner() > > This is clearly a race. We ended up in a state where both spice-gtk and > vdagent thinks the other component can provide the data, but in reality none > of them can. > > (This does not happen always, as can be seen in the log, the first paste > succeeds.) > > Given current spice protocol, I don't see a way to detect the race on either > side, but I'd love to be wrong. So I'd update the commit log and comment in > the code to explain the situation and then it's ack from me. > > Cheers, > Jakub > > On Mon, Jan 14, 2019, 1:34 PM Victor Toso <victort...@redhat.com wrote: >> >> From: Victor Toso <m...@victortoso.com> >> >> On X11, the release-grab message might end up clearing the >> GtkClipboard which triggers the owner-changed callback having the >> event owner as NULL. >> >> We should not be calling gtk_clipboard_request_targets() in this >> situation as is prone to errors as the intention here is request >> clipboard information from changes made by client OS. >> >> The fix is to avoid any such request while spice client is holding the >> keyboard grab. >> >> Related: https://gitlab.freedesktop.org/spice/win32/vd_agent/issues/6 >> Related: https://gitlab.freedesktop.org/spice/linux/vd_agent/issues/9 >> Related: https://bugzilla.redhat.com/show_bug.cgi?id=1594876 >> >> Changed in v4: >> - Updated commit log >> >> Signed-off-by: Victor Toso <victort...@redhat.com> >> Tested-by: James Harvey @jamespharvey20 >> --- >> src/spice-gtk-session.c | 13 +++++++++++++ >> 1 file changed, 13 insertions(+) >> >> diff --git a/src/spice-gtk-session.c b/src/spice-gtk-session.c >> index abce43f..20df70d 100644 >> --- a/src/spice-gtk-session.c >> +++ b/src/spice-gtk-session.c >> @@ -674,6 +674,19 @@ static void clipboard_owner_change(GtkClipboard >> *clipboard, >> return; >> } >> >> +#ifdef GDK_WINDOWING_X11 >> + /* In X11, while holding the keyboard-grab we are not interested in this >> + * event as it either came by grab or release messages from agent. */ >> + if (GDK_IS_X11_DISPLAY(gdk_display_get_default()) && >> + spice_gtk_session_get_keyboard_has_focus(self)) { >> + SPICE_DEBUG("clipboard: owner-changed event: not requesting >> client's target " >> + "while holding focus"); >> + return; >> + } >> +#endif >> + SPICE_DEBUG("clipboard: owner-changed event: has-focus=%d", >> + spice_gtk_session_get_keyboard_has_focus(self)); >> + >> s->clipboard_by_guest[selection] = FALSE; >> s->clip_hasdata[selection] = TRUE; >> if (s->auto_clipboard_enable && !read_only(self)) >> -- >> 2.20.1 >> _______________________________________________ Spice-devel mailing list Spice-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/spice-devel
