Segmentation fault when opening CLions settings window in certain situations about labwc

[Consolatis]

Thanks for reporting and the confirmation!
I will write up the PR with the quick and dirty option for now (unless you want to instead?).

[jp7677]

unless you want to instead?

I can do that, just give me a minute.

[Consolatis]

:)

PS: Being able to run labwc nested is so convenient for gathering this kind of information!

And yes, absolutely! Having to restart the main DRM session all the time during development or debugging would be a nightmare for me.

[johanmalm]

Thanks @jp7677
Really nice to get this fix in before the release.

[Consolatis]

Hm.. so surface->parent is != NULL but it seems ->data is. Hrm.
Could you add something like wlr_log(WLR_ERROR, "parent: %p", parent); in there?

Edit:
I assume what is happening here is that the parent of the managed X11 surface is in fact an unmanaged X11 surface which doesn't set the ->data pointer as doesn't have a view. So if the wlr_log() indeed confirms parent to be NULL we have two options:

• the quick and dirty one: just modifying the return to if (!parent || !parent->toplevel.handle)
• the proper one: loop through all parents until we find a toplevel handle or the parent is NULL

As we actually intended to release today I'd be fine with the quick and dirty one if its confirmed that it fixes the crash.
CC @johanmalm @jlindgren90

[jp7677]

Adding the log statement indeed confirms what you wrote:

[../src/xwayland.c:546] parent: (nil)

[jp7677]

Using above quick fix does indeed fixes the segfault. The settings window also opens after the click.

diff --git a/src/xwayland.c b/src/xwayland.c
index b109b1f..0c44b7c 100644
--- a/src/xwayland.c
+++ b/src/xwayland.c
@@ -543,7 +543,7 @@ init_foreign_toplevel(struct view *view)
                return;
        }
        struct view *parent = (struct view *)surface->parent->data;
-       if (!parent->toplevel.handle) {
+       if (!parent || !parent->toplevel.handle) {
                return;
        }
        wlr_foreign_toplevel_handle_v1_set_parent(view->toplevel.handle, parent->toplevel.handle);