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Created attachment 1455028[details]
video of bug
Description of problem:
Gnome-shell in VNC session eats up all cpu resources and VNC screen is corrupted after resizing vncviewer window to very small.
Version-Release number of selected component (if applicable):
tigervnc-1.8.0-7.el7.x86_64
gnome-shell-3.28.2-1.el7.x86_64
How reproducible:
always
Steps to Reproduce:
1. $ vncserver :1
2. $ vncviewer :1
3. resize vncviewer window to smallest possible
(4. resize vncviewer window to other sizes)
Actual results:
corrupted vnc screen and high cpu usage caused by gnome-shell
Expected results:
vnc screen should resize and look correct, no high cpu usage should be observed
Additional info:
Closing and starting vncviewer again does not help. Killing gnome-shell for vnc session helps, it restarts itself and works correctly afterwards.
Gnome was rebased in RHEL 7.6, still could be a cause as you say that the high cpu usage is caused by gnome-shell. In tigervnc there is nothing what changed between RHEL 7.5 and RHEL 7.6, just support for Xorg 1.20. Is there anything in vnc log?
Created attachment 1455053[details]
vnc log
Nothing really suspicious, only that there are no pixels sent when resizing after hitting bug.
ComparingUpdateTracker: 0 pixels in / 0 pixels out
ComparingUpdateTracker: (1:-nan ratio)
Yes, I tested it on RHEL 7.5 with just Xorg and tigervnc updated and the bug occurs also there.
xorg-x11-server-Xorg-1.20.0-0.3.el7.x86_64
tigervnc*-1.8.0-7.el7.x86_64
gnome-shell-3.26.2-5.el7.x86_64
gnome-session-3.26.1-11.el7.x86_64
gnome-desktop3-3.22.2-2.el7.x86_64
@ajax, do you have any idea whether this could be related to new Xorg? The only thing that changed is the patch we carry to suport Xorg 1.20 in tigervnc, but there is nothing I can think of what could break this. Major difference is the new Xorg 1.20. I checked all resize calls and hooks related to this and size is propagated properly. Is there anything I can provide you to nail down this issue?
This is reproducible only when the window gets really small which is not a common thing to do. I'm closing this now as only critical issues will be fixed in this phase of RHEL 7 and we don't know whether the issue is in Xorg or Tigervnc.
Created attachment 1455028 [details] video of bug Description of problem: Gnome-shell in VNC session eats up all cpu resources and VNC screen is corrupted after resizing vncviewer window to very small. Version-Release number of selected component (if applicable): tigervnc-1.8.0-7.el7.x86_64 gnome-shell-3.28.2-1.el7.x86_64 How reproducible: always Steps to Reproduce: 1. $ vncserver :1 2. $ vncviewer :1 3. resize vncviewer window to smallest possible (4. resize vncviewer window to other sizes) Actual results: corrupted vnc screen and high cpu usage caused by gnome-shell Expected results: vnc screen should resize and look correct, no high cpu usage should be observed Additional info: Closing and starting vncviewer again does not help. Killing gnome-shell for vnc session helps, it restarts itself and works correctly afterwards.