Segmentation fault at startup

[zjeffer]

I've been using wdisplays for a couple of weeks/months but today it crashed at startup:

Backtrace

(gdb) bt
#0  0x000055555556885c in resize (output=0x5555558ece00) at ../src/overlay.c:65
#1  0x0000555555568b73 in window_map (widget=0x5555558ed390 [GtkWindow], data=0x5555558ece00) at ../src/overlay.c:138
#2  0x00007ffff6cfe64a in g_closure_invoke (closure=0x5555558ee020, return_value=0x0, n_param_values=1, param_values=0x7fffffffc120, invocation_hint=0x7fffffffc070) at ../glib/gobject/gclosure.c:834
#3  0x00007ffff6d2ece5 in signal_emit_unlocked_R.isra.0 (node=node@entry=0x7fffffffc1f0, detail=detail@entry=0, instance=instance@entry=0x5555558ed390, emission_return=emission_return@entry=0x0, instance_and_params=instance_and_params@entry=0x7fffffffc120)
    at ../glib/gobject/gsignal.c:3888
#4  0x00007ffff6d1f5dc in signal_emit_valist_unlocked (instance=instance@entry=0x5555558ed390, signal_id=signal_id@entry=71, detail=detail@entry=0, var_args=var_args@entry=0x7fffffffc360) at ../glib/gobject/gsignal.c:3520
#5  0x00007ffff6d1f842 in g_signal_emit_valist (instance=0x5555558ed390, signal_id=71, detail=0, var_args=var_args@entry=0x7fffffffc360) at ../glib/gobject/gsignal.c:3263
#6  0x00007ffff6d1f904 in g_signal_emit (instance=<optimized out>, signal_id=<optimized out>, detail=<optimized out>) at ../glib/gobject/gsignal.c:3583
#7  0x00007ffff76bdd1a in gtk_widget_map (widget=0x5555558ed390 [GtkWindow]) at ../gtk/gtkwidget.c:5051
#8  0x00007ffff76e9085 in gtk_window_show (widget=0x5555558ed390 [GtkWindow]) at ../gtk/gtkwindow.c:6210
#9  0x00007ffff6cfe64a in g_closure_invoke (closure=0x555555609ea0, return_value=0x0, n_param_values=1, param_values=0x7fffffffc6d0, invocation_hint=0x7fffffffc620) at ../glib/gobject/gclosure.c:834
#10 0x00007ffff6d2ee22 in signal_emit_unlocked_R.isra.0 (node=node@entry=0x7fffffffc7a0, detail=detail@entry=0, instance=instance@entry=0x5555558ed390, emission_return=emission_return@entry=0x0, instance_and_params=instance_and_params@entry=0x7fffffffc6d0)
    at ../glib/gobject/gsignal.c:3721
#11 0x00007ffff6d1f5dc in signal_emit_valist_unlocked (instance=instance@entry=0x5555558ed390, signal_id=signal_id@entry=69, detail=detail@entry=0, var_args=var_args@entry=0x7fffffffc910) at ../glib/gobject/gsignal.c:3520
#12 0x00007ffff6d1f842 in g_signal_emit_valist (instance=0x5555558ed390, signal_id=69, detail=0, var_args=var_args@entry=0x7fffffffc910) at ../glib/gobject/gsignal.c:3263
#13 0x00007ffff6d1f904 in g_signal_emit (instance=<optimized out>, signal_id=<optimized out>, detail=<optimized out>) at ../glib/gobject/gsignal.c:3583
#14 0x00007ffff76bd583 in gtk_widget_show (widget=0x5555558ed390 [GtkWindow]) at ../gtk/gtkwidget.c:4852
#15 0x0000555555568eb1 in wd_create_overlay (output=0x5555558ece00) at ../src/overlay.c:188
#16 0x0000555555568053 in wd_add_output (state=0x5555556a65d0, wl_output=0x55555557db70, display=0x5555555a43e0) at ../src/outputs.c:624
#17 0x000055555556358f in activate (app=0x555555587560 [GtkApplication], user_data=0x0) at ../src/main.c:1071
#18 0x00007ffff6cfe64a in g_closure_invoke (closure=0x555555588d80, return_value=0x0, n_param_values=1, param_values=0x7fffffffcd80, invocation_hint=0x7fffffffccd0) at ../glib/gobject/gclosure.c:834
#19 0x00007ffff6d2ece5 in signal_emit_unlocked_R.isra.0 (node=node@entry=0x7fffffffce50, detail=detail@entry=0, instance=instance@entry=0x555555587560, emission_return=emission_return@entry=0x0, instance_and_params=instance_and_params@entry=0x7fffffffcd80)
    at ../glib/gobject/gsignal.c:3888
#20 0x00007ffff6d1f5dc in signal_emit_valist_unlocked (instance=instance@entry=0x555555587560, signal_id=signal_id@entry=8, detail=detail@entry=0, var_args=var_args@entry=0x7fffffffcfc0) at ../glib/gobject/gsignal.c:3520
#21 0x00007ffff6d1f842 in g_signal_emit_valist (instance=0x555555587560, signal_id=8, detail=0, var_args=var_args@entry=0x7fffffffcfc0) at ../glib/gobject/gsignal.c:3263
#22 0x00007ffff6d1f904 in g_signal_emit (instance=instance@entry=0x555555587560, signal_id=<optimized out>, detail=detail@entry=0) at ../glib/gobject/gsignal.c:3583
#23 0x00007ffff6f74158 in g_application_activate (application=0x555555587560 [GtkApplication]) at ../glib/gio/gapplication.c:2451
#24 0x00007ffff6f778e1 in g_application_real_local_command_line (application=0x555555587560 [GtkApplication], arguments=0x7fffffffd158, exit_status=0x7fffffffd154) at ../glib/gio/gapplication.c:1188
#25 0x00007ffff72d4cf9 in gtk_application_local_command_line (application=0x555555587560 [GtkApplication], arguments=0x7fffffffd158, exit_status=0x7fffffffd154) at ../gtk/gtkapplication.c:343
#26 0x00007ffff6f77a87 in g_application_run (application=0x555555587560 [GtkApplication], argc=<optimized out>, argv=0x7fffffffd2f8) at ../glib/gio/gapplication.c:2681
#27 0x000055555556372b in main (argc=1, argv=0x7fffffffd2f8) at ../src/main.c:1088
(gdb) 

Using Hyprland on Arch:

output of `hyprctl systeminfo`

Hyprland, built from branch main at commit 337422911895bb55099e00208bff929651dcb5d2  (core: remove unused includes and fix warn).
Date: Fri May 10 04:20:26 2024
Tag: v0.40.0-50-g33742291, commits: 4656

flags: (if any)


System Information:
System name: Linux
Node name: zjeffer
Release: 6.8.9-arch1-2
Version: #1 SMP PREEMPT_DYNAMIC Tue, 07 May 2024 21:35:54 +0000


GPU information: 
01:00.0 VGA compatible controller [0300]: NVIDIA Corporation GA104M [GeForce RTX 3070 Mobile / Max-Q] [10de:24dd] (rev a1) (prog-if 00 [VGA controller])


os-release: NAME="Arch Linux"
PRETTY_NAME="Arch Linux"
ID=arch
BUILD_ID=rolling
ANSI_COLOR="38;2;23;147;209"
HOME_URL="https://archlinux.org/"
DOCUMENTATION_URL="https://wiki.archlinux.org/"
SUPPORT_URL="https://bbs.archlinux.org/"
BUG_REPORT_URL="https://gitlab.archlinux.org/groups/archlinux/-/issues"
PRIVACY_POLICY_URL="https://terms.archlinux.org/docs/privacy-policy/"
LOGO=archlinux-logo


plugins:
  split-monitor-workspaces by Duckonaut ver 1.1.0

Happens both on latest release (wdisplays arch package) and latest master (manual build)

[zjeffer]

Apparantly the return value of wd_find_head is NULL

wdisplays/src/overlay.c

Lines 62 to 66 in 6233901

	static void resize(struct wd_output *output) {
	struct wd_head *head = wd_find_head(output->state, output);
	uint32_t screen_width = head->custom_mode.width;
	uint32_t screen_height = head->custom_mode.height;

If I add this on line 64:

  if (head == NULL) {
    printf("No head found for output %s\n", output->name);
    return;
  }

then Hyprland completely crashes, here are the last lines in the logfile:

hyprland log

[LOG] Window 60882389a020 set title to overlay.c - wdisplays - Visual Studio Code
[LOG] cursorImage request: surface 6088238d5f30
[LOG] cursorImage request: surface 6088238d5f30
[LOG] LayerSurface 1 destroyed
[LOG] Removing LayerSurface that wasn't mapped.
[LOG] Callback 608823884010 -> 608823884008, CWLSurface removed.
[LOG] Callback 608823884078 -> 608823884070, CWLSurface removed.
[LOG] CWLSurface 608823883f68 called destroy()
[LOG] LayerSurface 0 destroyed
[LOG] Callback 60881186b758 -> 60881186b750, CLayerShellResource removed.
[LOG] Callback 60881186b6f0 -> 60881186b6e8, CLayerShellResource removed.
[LOG] Callback 608811931168 -> 608811931160, FractionalScale removed.
[LOG] Cleanup: destroyed a layersurface
[LOG] cursorImage request: surface 6088238d5f30
[LOG] cursorImage request: surface 6088238d5f30
[LOG] [OutputManagement] New OutputManager registered
[LOG] [OutputManagement]  | sending output head for DP-1
[LOG] [OutputManagement]   | sending mode 1920x1080@60000mHz, pref: true
[LOG] [OutputManagement]   | sending mode 1680x1050@59954mHz, pref: false
[LOG] [OutputManagement]   | sending mode 1280x1024@75025mHz, pref: false
[LOG] [OutputManagement]   | sending mode 1280x1024@60020mHz, pref: false
[LOG] [OutputManagement]   | sending mode 1440x900@59887mHz, pref: false
[LOG] [OutputManagement]   | sending mode 1280x960@60000mHz, pref: false
[LOG] [OutputManagement]   | sending mode 1280x800@59810mHz, pref: false
[LOG] [OutputManagement]   | sending mode 1152x864@75000mHz, pref: false
[LOG] [OutputManagement]   | sending mode 1280x720@60000mHz, pref: false
[LOG] [OutputManagement]   | sending mode 1024x768@75029mHz, pref: false
[LOG] [OutputManagement]   | sending mode 1024x768@70069mHz, pref: false
[LOG] [OutputManagement]   | sending mode 1024x768@60004mHz, pref: false
[LOG] [OutputManagement]   | sending mode 800x600@75000mHz, pref: false
[LOG] [OutputManagement]   | sending mode 800x600@72188mHz, pref: false
[LOG] [OutputManagement]   | sending mode 800x600@60317mHz, pref: false
[LOG] [OutputManagement]   | sending mode 800x600@56250mHz, pref: false
[LOG] [OutputManagement]   | sending mode 640x480@75000mHz, pref: false
[LOG] [OutputManagement]   | sending mode 640x480@72809mHz, pref: false
[LOG] [OutputManagement]   | sending mode 640x480@59940mHz, pref: false
[LOG] [OutputManagement]   | sending current mode for DP-1: 1920x1080@60000
[LOG] [OutputManagement]  | sending output head for DP-2
[LOG] [OutputManagement]   | sending mode 1920x1080@60000mHz, pref: true
[LOG] [OutputManagement]   | sending mode 1920x1080@59939mHz, pref: false
[LOG] [OutputManagement]   | sending mode 1920x1080@50000mHz, pref: false
[LOG] [OutputManagement]   | sending mode 1920x1080@25000mHz, pref: false
[LOG] [OutputManagement]   | sending mode 1920x1080@24000mHz, pref: false
[LOG] [OutputManagement]   | sending mode 1920x1080@23977mHz, pref: false
[LOG] [OutputManagement]   | sending mode 1280x1024@60020mHz, pref: false
[LOG] [OutputManagement]   | sending mode 1280x720@59943mHz, pref: false
[LOG] [OutputManagement]   | sending mode 1280x720@50000mHz, pref: false
[LOG] [OutputManagement]   | sending mode 1024x768@60004mHz, pref: false
[LOG] [OutputManagement]   | sending mode 800x600@60317mHz, pref: false
[LOG] [OutputManagement]   | sending mode 720x576@50000mHz, pref: false
[LOG] [OutputManagement]   | sending mode 720x480@59940mHz, pref: false
[LOG] [OutputManagement]   | sending mode 640x480@59940mHz, pref: false
[LOG] [OutputManagement]   | sending mode 640x480@59929mHz, pref: false
[LOG] [OutputManagement]   | sending current mode for DP-2: 1920x1080@60000
[LOG] [OutputManagement]  | sending output head for HDMI-A-1
[LOG] [OutputManagement]   | sending mode 1920x1080@60000mHz, pref: true
[LOG] [OutputManagement]   | sending mode 1920x1080@59939mHz, pref: false
[LOG] [OutputManagement]   | sending mode 1920x1080@50000mHz, pref: false
[LOG] [OutputManagement]   | sending mode 1680x1050@59954mHz, pref: false
[LOG] [OutputManagement]   | sending mode 1280x1024@75025mHz, pref: false
[LOG] [OutputManagement]   | sending mode 1280x1024@60020mHz, pref: false
[LOG] [OutputManagement]   | sending mode 1440x900@74984mHz, pref: false
[LOG] [OutputManagement]   | sending mode 1440x900@59887mHz, pref: false
[LOG] [OutputManagement]   | sending mode 1280x960@60000mHz, pref: false
[LOG] [OutputManagement]   | sending mode 1280x720@60000mHz, pref: false
[LOG] [OutputManagement]   | sending mode 1280x720@59943mHz, pref: false
[LOG] [OutputManagement]   | sending mode 1280x720@50000mHz, pref: false
[LOG] [OutputManagement]   | sending mode 1024x768@75029mHz, pref: false
[LOG] [OutputManagement]   | sending mode 1024x768@60004mHz, pref: false
[LOG] [OutputManagement]   | sending mode 800x600@75000mHz, pref: false
[LOG] [OutputManagement]   | sending mode 800x600@60317mHz, pref: false
[LOG] [OutputManagement]   | sending mode 720x576@50000mHz, pref: false
[LOG] [OutputManagement]   | sending mode 720x480@59940mHz, pref: false
[LOG] [OutputManagement]   | sending mode 640x480@75000mHz, pref: false
[LOG] [OutputManagement]   | sending mode 640x480@72809mHz, pref: false
[LOG] [OutputManagement]   | sending mode 640x480@59940mHz, pref: false
[LOG] [OutputManagement]   | sending mode 640x480@59929mHz, pref: false
[LOG] [OutputManagement]   | sending current mode for HDMI-A-1: 1920x1080@60000
[LOG] [OutputManagement]  | sending output head for eDP-1
[LOG] [OutputManagement]   | sending mode 2560x1600@60008mHz, pref: true
[LOG] [OutputManagement]   | sending mode 2560x1600@165019mHz, pref: false
[LOG] [OutputManagement]   | sending current mode for eDP-1: 2560x1600@165019
[LOG] ScreencopyProtocolManager bound successfully!
[LOG] [TextInputV3] New tiv3 at 00006088121f7d70
[LOG] Registered signal for owner 60881186b4e0: 6088121cf088 -> 60881186b6c8 (owner: CLayerShellResource)
[LOG] Registered signal for owner 60881186b4e0: 6088121cf048 -> 60881186b730 (owner: CLayerShellResource)
[LOG] Registered signal for owner 608823883f68: 6088121cf088 -> 608823883fe8 (owner: CWLSurface)
[LOG] Registered signal for owner 608823883f68: 6088121cf048 -> 608823884050 (owner: CWLSurface)
[LOG] CWLSurface 608823883f68 called init()
[LOG] LayerSurface 60881186b4e0 (namespace output-overlay layer 2) created on monitor DP-1
[LOG] [LayerShell] New wlr_layer_surface 60881186b4e0
[LOG] Registered signal for owner 6088121ced70: 6088121cf088 -> 608811b00a30 (owner: FractionalScale)
[LOG] Registered signal for owner 60882386fff0: 6088238abee8 -> 6088238701d8 (owner: CLayerShellResource)
[LOG] Registered signal for owner 60882386fff0: 6088238abea8 -> 608823870240 (owner: CLayerShellResource)
[LOG] Registered signal for owner 6088121e2e88: 6088238abee8 -> 6088121e2f08 (owner: CWLSurface)
[LOG] Registered signal for owner 6088121e2e88: 6088238abea8 -> 6088121e2f70 (owner: CWLSurface)
[LOG] CWLSurface 6088121e2e88 called init()
[LOG] LayerSurface 60882386fff0 (namespace output-overlay layer 2) created on monitor HDMI-A-1
[LOG] [LayerShell] New wlr_layer_surface 60882386fff0
[LOG] Registered signal for owner 6088118983c0: 608823892018 -> 6088118985a8 (owner: CLayerShellResource)
[LOG] Registered signal for owner 6088118983c0: 608823891fd8 -> 608811898610 (owner: CLayerShellResource)
[LOG] Registered signal for owner 6088238ac8e8: 608823892018 -> 6088238ac968 (owner: CWLSurface)
[LOG] Registered signal for owner 6088238ac8e8: 608823891fd8 -> 6088238ac9d0 (owner: CWLSurface)
[LOG] CWLSurface 6088238ac8e8 called init()
[LOG] LayerSurface 6088118983c0 (namespace output-overlay layer 2) created on monitor HDMI-A-1
[LOG] [LayerShell] New wlr_layer_surface 6088118983c0
[LOG] Registered signal for owner 608823891d00: 608823892018 -> 6088238acc10 (owner: FractionalScale)
[LOG] Registered signal for owner 608811a3ff10: 6088121e29b8 -> 608811a400f8 (owner: CLayerShellResource)
[LOG] Registered signal for owner 608811a3ff10: 6088121e2978 -> 608811a40160 (owner: CLayerShellResource)
[LOG] Registered signal for owner 608823883848: 6088121e29b8 -> 6088238838c8 (owner: CWLSurface)
[LOG] Registered signal for owner 608823883848: 6088121e2978 -> 608823883930 (owner: CWLSurface)
[LOG] CWLSurface 608823883848 called init()
[LOG] LayerSurface 608811a3ff10 (namespace output-overlay layer 2) created on monitor eDP-1
[LOG] [LayerShell] New wlr_layer_surface 608811a3ff10
[LOG] Registered signal for owner 6088121e26a0: 6088121e29b8 -> 6088238b0d80 (owner: FractionalScale)
[LOG] New XDG Toplevel created. (class: null)
[LOG] Registered signal for owner 6088238f1730: 6088121f5898 -> 6088238f1798 (owner: XDG Window)
[LOG] Registered signal for owner 6088238f1730: 608813812358 -> 6088238f1868 (owner: XDG Window)
[LOG] Registered signal for owner 6088238f1730: 6088121f5888 -> 6088238f1730 (owner: XDG Window)
[LOG] Registered signal for owner 6088238f1f50: 6088121f58c8 -> 6088238f1fd0 (owner: CWLSurface)
[LOG] Registered signal for owner 6088238f1f50: 6088121f5888 -> 6088238f2038 (owner: CWLSurface)
[LOG] CWLSurface 6088238f1f50 called init()
[LOG] Searching for matching rules for wdisplays (title: wdisplays)
[LOG] Layout predicts size [Vector2D: x: 960, y: 1040] for [Window 6088238f1730: title: ""]
[ERR] client requested sharing of a monitor that doesnt exist

[zjeffer]

Figured it out: it only happens when one of my monitors is mirroring another one. If I disconnect my mirrored monitor, it doesn't segfault.

Does wdisplays not support mirroring?