System.NullReferenceException at System.Windows.Forms.Hwnd.AddInvalidArea after 10-20 minutes runtime with aggressive Control.Invalidate() calls #21806
Description
Steps to Reproduce
- do agressive Control.Invalidate() calls (50 frames per second) from background thread with the following OnPaint code until exception happens:
protected override void OnPaint(PaintEventArgs e)
{
e.Graphics.InterpolationMode = InterpolationMode.NearestNeighbor;
e.Graphics.DrawImage(drawImage, drawRect);
var rect = new Rectangle(new Point(0, 0), new Size(ClientSize.Width, ClientSize.Height));
var region = new Region(rect);
region.Exclude(drawRect);
e.Graphics.FillRegion(Brushes.Black, region);
}
The issue is stable reproduced, but requires to wait for a long time.
Current Behavior
After some long period (5-20 minutes) the exception System.NullReferenceException is thrown and no more window paint
Expected Behavior
Expected no exception
On which platforms did you notice this
Linux Raspberry Pi OS Bookworm (Wayland Wayfire) aarch64
$ uname -a
Linux raspi 6.6.51+rpt-rpi-v8 #1 SMP PREEMPT Debian 1:6.6.51-1+rpt3 (2024-10-08) aarch64 GNU/Linux
Version Used:
$ mono --version
Mono JIT compiler version 6.12.0.200 (tarball Tue Jul 11 21:44:02 UTC 2023)
Copyright (C) 2002-2014 Novell, Inc, Xamarin Inc and Contributors. www.mono-project.com
TLS: __thread
SIGSEGV: normal
Notifications: epoll
Architecture: arm64
Disabled: none
Misc: softdebug
Interpreter: yes
LLVM: yes(610)
Suspend: preemptive
GC: sgen (concurrent by default)
Stacktrace
System.NullReferenceException: Object reference not set to an instance of an object
at System.Windows.Forms.Hwnd.AddInvalidArea (System.Drawing.Rectangle rect) [0x0001a] in <25c2bdf9d79a43a599eb46bd15cd77fb>:0
at System.Windows.Forms.Hwnd.AddInvalidArea (System.Int32 x, System.Int32 y, System.Int32 width, System.Int32 height) [0x0000b] in <25c2bdf9d79a43a599eb46bd15cd77fb>:0
at System.Windows.Forms.XplatUIX11.AddExpose (System.Windows.Forms.Hwnd hwnd, System.Boolean client, System.Int32 x, System.Int32 y, System.Int32 width, System.Int32 height) [0x00057] in <25c2bdf9d79a43a599eb46bd15cd77fb>:0
at System.Windows.Forms.XplatUIX11.Invalidate (System.IntPtr handle, System.Drawing.Rectangle rc, System.Boolean clear) [0x0004a] in <25c2bdf9d79a43a599eb46bd15cd77fb>:0
at System.Windows.Forms.XplatUI.Invalidate (System.IntPtr handle, System.Drawing.Rectangle rc, System.Boolean clear) [0x00000] in <25c2bdf9d79a43a599eb46bd15cd77fb>:0
at System.Windows.Forms.Control.Invalidate (System.Drawing.Rectangle rc, System.Boolean invalidateChildren) [0x00041] in <25c2bdf9d79a43a599eb46bd15cd77fb>:0
at System.Windows.Forms.Control.Invalidate ()
at TEST.TestControl.RequestUpdate() [0x001b6] in <61967c82b0984a6b8723cdd11864b85f>:0