GUI daemon crashes on XShmPutImage

[marmarek]

Error message in logs:

 ErrorHandler: BadValue (integer parameter out of range for operation) 
 Major opcode: 130 (MIT-SHM) 
 Minor opcode: 3 (X_ShmPutImage) 
 Value: 0x2df 
 Failed serial number: 173 
 Current serial number: 174

It looks to me that XSync isn't effective anymore and the call is executed asynchronously anyway. Looks like very similar problem to #2085
Originally reported in #2120

[marmarek]

Even more technical details from debugging this - shared memory segment as seen by Xorg server here, has size of 1 byte, which is obviously wrong. It looks like shmoverride didn't intercepted the right shmat call, and the dummy region (of size 1) is attached, instead of actual pages from selected domain.
Documentation and the code:
https://github.com/QubesOS/qubes-gui-daemon/tree/master/shmoverride
https://github.com/QubesOS/qubes-gui-daemon/blob/master/gui-daemon/xside.c#L2283-L2311

[marmarek]

Even more technical details from debugging this - shared memory segment as seen by Xorg server here, has size of 1 byte, which is obviously wrong. It looks like shmoverride didn't intercepted the right shmat call, and the dummy region (of size 1) is attached, instead of actual pages from selected domain.
Documentation and the code:
https://github.com/QubesOS/qubes-gui-daemon/tree/master/shmoverride
https://github.com/QubesOS/qubes-gui-daemon/blob/master/gui-daemon/xside.c#L2283-L2311

[marmarek]

@rootkovska do you get any VM window working when this happens? In the case I'm debugging right now, the whole shmoverride failed to initialize, so no window is visible. For some yet unknown reason, only gui-daemon of sys-net crashes - probably because it is the only one trying to show something (nm-applet).
You can check /var/log/lightdm/x-0.log for some shmoverride initialization error message just at the beginning.

[marmarek]

@rootkovska do you get any VM window working when this happens? In the case I'm debugging right now, the whole shmoverride failed to initialize, so no window is visible. For some yet unknown reason, only gui-daemon of sys-net crashes - probably because it is the only one trying to show something (nm-applet).
You can check /var/log/lightdm/x-0.log for some shmoverride initialization error message just at the beginning.

[marmarek]

This was caused by starting second X server (by either light-locker, or "new session" feature), which we consider as invalid operation.

[marmarek]

This was caused by starting second X server (by either light-locker, or "new session" feature), which we consider as invalid operation.

[marmarek]

Automated announcement from builder-github

The package qubes-gui-dom0-3.2.3-1.fc23 has been pushed to the r3.2 testing repository for dom0.
To test this update, please install it with the following command:

sudo qubes-dom0-update --enablerepo=qubes-dom0-current-testing

Changes included in this update

[marmarek]

Automated announcement from builder-github

The package qubes-gui-dom0-3.2.3-1.fc23 has been pushed to the r3.2 testing repository for dom0.
To test this update, please install it with the following command:

sudo qubes-dom0-update --enablerepo=qubes-dom0-current-testing

Changes included in this update

[marmarek]

Automated announcement from builder-github

The package qubes-gui-dom0-3.2.3-1.fc23 has been pushed to the r3.2 stable repository for dom0.
To install this update, please use the standard update command:

sudo qubes-dom0-update

Or update dom0 via Qubes Manager.

Changes included in this update

[marmarek]

Automated announcement from builder-github

The package qubes-gui-dom0-3.2.3-1.fc23 has been pushed to the r3.2 stable repository for dom0.
To install this update, please use the standard update command:

sudo qubes-dom0-update

Or update dom0 via Qubes Manager.

Changes included in this update