Gnome-shell crashes when we use "workspace-grid" extension ( affects gnome-shell=3.30.2 )

[harish2704]

Since version 3.30.2 Gnome shell is crashing when we use use "workspace-grid" extension.

Details

• Gnome-shell version: 3.30.2
• workspace-grid version: 29
• OS : OpenSUSE Tumbleweed

workspace grid configuration:

Stack trace

Core was generated by `/usr/bin/gnome-shell'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0  meta_compositor_switch_workspace (compositor=0x0, from=0x55cb5adb9130, to=<optimized out>, direction=META_MOTION_DOWN)
    at compositor/compositor.c:832
832	  compositor->switch_workspace_in_progress++;
[Current thread is 1 (Thread 0x7f32527c5b00 (LWP 1853))]
(gdb) bt full
#0  0x00007f325b68f115 in meta_compositor_switch_workspace
    (compositor=0x0, from=0x55cb5adb9130, to=<optimized out>, direction=META_MOTION_DOWN) at compositor/compositor.c:832
        to_indx = 1
        from_indx = 0
#1  0x00007f325b6c7d13 in meta_workspace_activate_with_focus
    (workspace=0x55cb5adb91c0, focus_this=focus_this@entry=0x0, timestamp=timestamp@entry=26055067) at core/workspace.c:636
        old = 0x55cb5adb9130
        move_window = <optimized out>
        comp = 0x0
        layout1 = {rows = 18, cols = 1, grid = 0x55cb5b131130, grid_area = 18, current_row = 0, current_col = 0}
        layout2 = {rows = 18, cols = 1, grid = 0x55cb5b0f1e50, grid_area = 18, current_row = 1, current_col = 0}
        num_workspaces = <optimized out>
        current_space = <optimized out>
        new_space = <optimized out>
        direction = META_MOTION_DOWN
#2  0x00007f325b6c7f99 in meta_workspace_activate (workspace=<optimized out>, timestamp=timestamp@entry=26055067) at core/workspace.c:665
#3  0x00007f325b6d073c in meta_x11_display_new (display=display@entry=0x55cb5b0c6090, error=error@entry=0x7ffdcabd0eb8)
    at x11/meta-x11-display.c:1300
        x11_display = 0x55cb5abfc420
        xdisplay = 0x55cb5abc1b70
        xscreen = <optimized out>
        xroot = 278
        i = 123
        number = 0
        new_wm_sn_owner = <optimized out>
        replace_current_wm = 0
        wm_sn_atom = 562
        buf = "WM_S0", '\000' <repeats 122 times>
        timestamp = 26055067
        current_workspace = <optimized out>
        current_workspace_index = 1
        atom_restart_helper = 532
        restart_helper_window = <optimized out>
        gdk_display = <optimized out>
        backend = <optimized out>
        monitor_manager = <optimized out>
        atom_names = 
          {0x7f325b7442cc "WM_PROTOCOLS", 0x7f325b7442d9 "WM_TAKE_FOCUS", 0x7f325b7442e7 "WM_DELETE_WINDOW", 0x7f325b74455d "WM_STATE", 0x7f32--Type <RET> for more, q to quit, c to continue without paging--c
5b7442f8 "_MOTIF_WM_HINTS", 0x7f325b744308 "WM_CHANGE_STATE", 0x7f325b744318 "SM_CLIENT_ID", 0x7f325b744325 "WM_CLIENT_LEADER", 0x7f325b744336 "WM_WINDOW_ROLE", 0x7f325b744345 "UTF8_STRING", 0x7f325b744351 "WM_ICON_SIZE", 0x7f325b74435e "_KWM_WIN_ICON", 0x7f325b740aae "_MUTTER_HINTS", 0x7f325b74436c "_GTK_THEME_VARIANT", 0x7f325b745298 "_GTK_HIDE_TITLEBAR_WHEN_MAXIMIZED", 0x7f325b740b07 "_GTK_APPLICATION_ID", 0x7f325b740b2e "_GTK_UNIQUE_BUS_NAME", 0x7f325b740b57 "_GTK_APPLICATION_OBJECT_PATH", 0x7f325b740b90 "_GTK_WINDOW_OBJECT_PATH", 0x7f325b740bbf "_GTK_APP_MENU_OBJECT_PATH", 0x7f325b740bf2 "_GTK_MENUBAR_OBJECT_PATH", 0x7f325b74437f "_GTK_FRAME_EXTENTS", 0x7f325b744392 "_GTK_SHOW_WINDOW_MENU", 0x7f325b7443a8 "_GTK_EDGE_CONSTRAINTS", 0x7f325b7443be "_GNOME_WM_KEYBINDINGS", 0x7f325b7443d4 "_GNOME_PANEL_ACTION", 0x7f325b7443e8 "_GNOME_PANEL_ACTION_MAIN_MENU", 0x7f325b7452c0 "_GNOME_PANEL_ACTION_RUN_DIALOG", 0x7f325b744406 "_MUTTER_TIMESTAMP_PING", 0x7f325b74441d "_MUTTER_FOCUS_SET", 0x7f325b74442f "_MUTTER_SENTINEL", 0x7f325b744440 "_MUTTER_VERSION", 0x7f325b744450 "WM_CLIENT_MACHINE", 0x7f325b744462 "MANAGER", 0x7f325b74446a "TARGETS", 0x7f325b744472 "MULTIPLE", 0x7f325b74447b "TIMESTAMP", 0x7f325b744448 "VERSION", 0x7f325b744485 "ATOM_PAIR", 0x7f325b74448f "_XKB_RULES_NAMES", 0x7f325b7444a0 "WL_SURFACE_ID", 0x7f325b7444ae "_XWAYLAND_MAY_GRAB_KEYBOARD", 0x7f325b7444ca "_NET_WM_SYNC_REQUEST", 0x7f325b7444df "_NET_WM_SYNC_REQUEST_COUNTER", 0x7f325b7444fc "_NET_WM_VISIBLE_NAME", 0x7f325b744511 "_NET_SUPPORTING_WM_CHECK", 0x7f325b74452a "_NET_SUPPORTED", 0x7f325b744539 "_NET_WM_NAME", 0x7f325b744546 "_NET_CLOSE_WINDOW", 0x7f325b744558 "_NET_WM_STATE", 0x7f325b744566 "_NET_WM_STATE_SHADED", 0x7f325b74457b "_NET_WM_STATE_MAXIMIZED_HORZ", 0x7f325b744598 "_NET_WM_STATE_MAXIMIZED_VERT", 0x7f325b7445b5 "_NET_WM_DESKTOP", 0x7f325b7445c5 "_NET_NUMBER_OF_DESKTOPS", 0x7f325b7445dd "_NET_CURRENT_DESKTOP", 0x7f325b7445f2 "_NET_WM_WINDOW_TYPE", 0x7f325b744606 "_NET_WM_WINDOW_TYPE_DESKTOP", 0x7f325b744622 "_NET_WM_WINDOW_TYPE_DOCK", 0x7f325b74463b "_NET_WM_WINDOW_TYPE_TOOLBAR", 0x7f325b744657 "_NET_WM_WINDOW_TYPE_MENU", 0x7f325b744670 "_NET_WM_WINDOW_TYPE_UTILITY", 0x7f325b74468c "_NET_WM_WINDOW_TYPE_SPLASH", 0x7f325b7446a7 "_NET_WM_WINDOW_TYPE_DIALOG", 0x7f325b7452e0 "_NET_WM_WINDOW_TYPE_DROPDOWN_MENU", 0x7f325b745308 "_NET_WM_WINDOW_TYPE_POPUP_MENU", 0x7f325b7446c2 "_NET_WM_WINDOW_TYPE_TOOLTIP", 0x7f325b745328 "_NET_WM_WINDOW_TYPE_NOTIFICATION", 0x7f325b7446de "_NET_WM_WINDOW_TYPE_COMBO", 0x7f325b7446f8 "_NET_WM_WINDOW_TYPE_DND", 0x7f325b744710 "_NET_WM_WINDOW_TYPE_NORMAL", 0x7f325b74472b "_NET_WM_STATE_MODAL", 0x7f325b74473f "_NET_CLIENT_LIST", 0x7f325b744750 "_NET_CLIENT_LIST_STACKING", 0x7f325b74476a "_NET_WM_STATE_SKIP_TASKBAR", 0x7f325b744785 "_NET_WM_STATE_SKIP_PAGER", 0x7f325b74479e "_NET_WM_ICON", 0x7f325b7447ab "_NET_WM_ICON_GEOMETRY", 0x7f325b7447c1 "_NET_WM_MOVERESIZE", 0x7f325b7447d4 "_NET_ACTIVE_WINDOW", 0x7f325b7447e7 "_NET_WM_STRUT", 0x7f325b7447f5 "_NET_WM_STATE_HIDDEN", 0x7f325b74480a "_NET_WM_STATE_FULLSCREEN", 0x7f325b744823 "_NET_WM_PING", 0x7f325b744830 "_NET_WM_PID", 0x7f325b74483c "_NET_WORKAREA", 0x7f325b74484a "_NET_SHOWING_DESKTOP", 0x7f325b74485f "_NET_DESKTOP_LAYOUT", 0x7f325b744873 "_NET_DESKTOP_NAMES", 0x7f325b744886 "_NET_WM_ALLOWED_ACTIONS", 0x7f325b74489e "_NET_WM_ACTION_MOVE", 0x7f325b7448b2 "_NET_WM_ACTION_RESIZE", 0x7f325b7448c8 "_NET_WM_ACTION_SHADE", 0x7f325b7448dd "_NET_WM_ACTION_STICK", 0x7f325b7448f2 "_NET_WM_ACTION_MAXIMIZE_HORZ", 0x7f325b74490f "_NET_WM_ACTION_MAXIMIZE_VERT", 0x7f325b74492c "_NET_WM_ACTION_CHANGE_DESKTOP", 0x7f325b74494a "_NET_WM_ACTION_CLOSE", 0x7f325b74495f "_NET_WM_STATE_ABOVE", 0x7f325b744973 "_NET_WM_STATE_BELOW", 0x7f325b744987 "_NET_STARTUP_ID", 0x7f325b744997 "_NET_WM_STRUT_PARTIAL", 0x7f325b7449ad "_NET_WM_ACTION_FULLSCREEN", 0x7f325b7449c7 "_NET_WM_ACTION_MINIMIZE", 0x7f325b7449df "_NET_FRAME_EXTENTS", 0x7f325b7449f2 "_NET_REQUEST_FRAME_EXTENTS", 0x7f325b744a0d "_NET_WM_USER_TIME", 0x7f325b745350 "_NET_WM_STATE_DEMANDS_ATTENTION", 0x7f325b744a1f "_NET_MOVERESIZE_WINDOW", 0x7f325b744a36 "_NET_DESKTOP_GEOMETRY", 0x7f325b744a4c "_NET_DESKTOP_VIEWPORT", 0x7f325b744a62 "_NET_WM_USER_TIME_WINDOW", 0x7f325b744a7b "_NET_WM_ACTION_ABOVE", 0x7f325b744a90 "_NET_WM_ACTION_BELOW", 0x7f325b744aa5 "_NET_WM_STATE_STICKY", 0x7f325b744aba "_NET_WM_FULLSCREEN_MONITORS", 0x7f325b744ad6 "_NET_WM_STATE_FOCUSED", 0x7f325b744aec "_NET_WM_BYPASS_COMPOSITOR", 0x7f325b744b06 "_NET_WM_OPAQUE_REGION", 0x7f325b744b1c "_NET_WM_FRAME_DRAWN", 0x7f325b744b30 "_NET_WM_FRAME_TIMINGS", 0x7f325b744b46 "_NET_WM_WINDOW_OPACITY", 0x7f325b744b5d "_NET_RESTACK_WINDOW"}
        atoms = {318, 320, 319, 327, 347, 328, 331, 329, 330, 399, 38, 533, 534, 535, 536, 537, 538, 539, 540, 541, 542, 543, 544, 510, 545, 546, 547, 548, 549, 550, 551, 552, 36, 325, 334, 335, 336, 553, 554, 314, 555, 556, 323, 324, 464, 394, 352, 357, 462, 362, 477, 366, 367, 466, 455, 458, 374, 375, 376, 377, 378, 379, 380, 381, 382, 383, 384, 385, 386, 387, 388, 368, 453, 454, 478, 479, 359, 469, 356, 397, 467, 480, 365, 321, 360, 354, 461, 460, 459, 472, 482, 483, 485, 486, 488, 487, 490, 491, 363, 364, 471, 468, 489, 484, 391, 557, 371, 370, 355, 456, 457, 372, 558, 559, 476, 473, 505, 496, 474, 560, 561, 361, 463}
        __func__ = "meta_x11_display_new"
#4  0x00007f325b6a689d in meta_display_open () at core/display.c:746
        error = 0x0
        display = 0x55cb5b0c6090
        x11_display = <optimized out>
        i = <optimized out>
        timestamp = <optimized out>
        old_active_xwindow = 0
        backend = 0x55cb5a90c130
        monitor_manager = <optimized out>
        settings = <optimized out>
        __func__ = "meta_display_open"
#5  0x00007f325b6b1bbc in meta_run () at core/main.c:686
#6  0x000055cb59a00782 in main (argc=<optimized out>, argv=<optimized out>) at ../src/main.c:501
        ctx = <optimized out>
        error = 0x0
        ecode = <optimized out>

How to reproduce this issue

• Enable workspace-grid extension
• place any two windows in two different workspaces ( for eg: for a 3x3 grid, I placed in top-centre and left-middle workspaces )
• Restart gnome shell by pressing r

Now Gnome-shell will crash

[harish2704]

I have reported this issue in gnome-shell's bug tracker too
https://gitlab.gnome.org/GNOME/gnome-shell/issues/823

[harish2704]

I did some debugging and I can confirm that, it is not a mutter bug.

Actual problem lies on this function call

  /* Get current workspace */
  if (meta_prop_get_cardinal (x11_display,
                              x11_display->xroot,
                              x11_display->atom__NET_CURRENT_DESKTOP,
                              &current_workspace_index))

@ https://gitlab.gnome.org/GNOME/mutter/blob/master/src/x11/meta-x11-display.c#L1308

which returns wrong value.

Due to that wrong value, the condition @ https://gitlab.gnome.org/GNOME/mutter/blob/master/src/core/workspace.c#L537

  if (workspace->manager->active_workspace == workspace)
    return;

evaluates false and the return statement is not evaluated.

This is the root cause of this bug.

failure to compute current_workspace_index can be due to wrong calculation done by workspace-grid extension or due to some API change in mutter.

[harish2704]

In 3x3 workspace grid, This bug happens only when I restart the shell from workspace other than workspace_no 1

It means, current_workspace_index is computed correctly if we are in first workspace and it fails when we are in other workspace.

it seems like a computation problem in grid layout

[stalet]

It also happens sometimes after unlocking a gnome session.

[mikehardy]

I was crashing with the latest updates that came down on Ubuntu 18.04.01 LTS (it was still gnome-shell 3.28.x) using workplace-grid from the gnome extensions site, but only when I was running Android emulators. If you switched away from a workspace with an emulator visible, it would crash with very similar results to those posted (though I was sadly unable to get apport-retrace to do anything useful for me...).

It seems to be working fine with Ubuntu 18.10 + gnome-shell 3.30.1 though. Have you tried reverting? I'm just curious because I did a full OS upgrade (18.04 -> 18.10) to access gnome-shell 3.30.x which is currently working for me. But if 3.30.2 is going to make me crashy again I'll know to wait...