Stack trace of the ~1s hang on the second call to GDKOpenGL::render:
    #0  0x00007ffff7a080bf in __GI___poll
        (fds=fds@entry=0x7fffffffc388, nfds=nfds@entry=1, timeout=timeout@entry=-1)
        at ../sysdeps/unix/sysv/linux/poll.c:29
    #1  0x00007ffff76d620b in poll (__timeout=-1, __nfds=1, __fds=0x7fffffffc388)
        at /usr/include/bits/poll2.h:39
    #2  _xcb_conn_wait
        (c=c@entry=0x11c0140, vector=vector@entry=0x0, count=count@entry=0x0, cond=<optimized out>)
        at /usr/src/debug/libxcb/libxcb-1.16.1/src/xcb_conn.c:510
    #3  0x00007ffff76d829b in _xcb_conn_wait
        (count=0x0, vector=0x0, cond=<optimized out>, c=0x11c0140)
        at /usr/src/debug/libxcb/libxcb-1.16.1/src/xcb_conn.c:476
    #4  xcb_wait_for_special_event (c=0x11c0140, se=0x35bca30)
        at /usr/src/debug/libxcb/libxcb-1.16.1/src/xcb_in.c:806
    #5  0x00007ffff5dad3bf in dri3_wait_for_event_locked ()
        at ../mesa-24.0.3/src/loader/loader_dri3_helper.c:591
    #6  dri3_wait_for_event_locked () at ../mesa-24.0.3/src/loader/loader_dri3_helper.c:572
    #7  0x00007ffff5dada12 in loader_dri3_wait_for_sbc ()
        at ../mesa-24.0.3/src/loader/loader_dri3_helper.c:664
    #8  loader_dri3_swapbuffer_barrier () at ../mesa-24.0.3/src/loader/loader_dri3_helper.c:2343
    #9  0x00007fffc48308da in dri_st_framebuffer_flush_swapbuffers ()
        at ../mesa-24.0.3/src/gallium/frontends/dri/dri_drawable.c:143
    #10 0x00007fffc48f6a99 in st_manager_flush_swapbuffers ()
        at ../mesa-24.0.3/src/mesa/state_tracker/st_manager.c:1270
    #11 st_finish () at ../mesa-24.0.3/src/mesa/state_tracker/st_cb_flush.c:85
    #12 0x00007fffc4a36421 in st_glFinish ()
        at ../mesa-24.0.3/src/mesa/state_tracker/st_cb_flush.c:109
    #13 _mesa_Finish () at ../mesa-24.0.3/src/mesa/main/context.c:1660
    #14 0x00007ffff6de8e8c in gdk_x11_gl_context_end_frame
        (context=0x32f8650 [GdkX11GLContext], painted=0x372ee50, damage=<optimized out>)
        at ../gtk/gdk/x11/gdkglcontext-x11.c:263
    #15 0x00007ffff6da4f6d in gdk_gl_context_end_frame
        (damage=0x0, painted=0x372ee50, context=0x32f8650 [GdkX11GLContext])
        at ../gtk/gdk/gdkglcontext.c:396
    #16 gdk_window_end_paint_internal (window=window@entry=0x3037a50 [GdkX11Window])
        at ../gtk/gdk/gdkwindow.c:3072
    #17 0x00007ffff6da50f7 in gdk_window_end_draw_frame
        (context=0x35bde50 [GdkDrawingContext], window=0x3037a50 [GdkX11Window])
        at ../gtk/gdk/gdkwindow.c:3311
    #18 gdk_window_end_draw_frame
        (window=0x3037a50 [GdkX11Window], context=0x35bde50 [GdkDrawingContext])
        at ../gtk/gdk/gdkwindow.c:3294
    #19 0x00007fffd782938e in GDKOpenGL::render (this=0x30134b0, userData=0x0)