A crash bring up the app_server in gdb when changing the screen resolution

[oco]

Reproducible on a fresh install after few change of the screen resolution (less than five) on my laptop (Vesa mode)

I use release hrev42926

Overview of the backtrace :

free
MallocBuffer::MallocBuffer
AccelerantHWInterface::SetMode
Screen::SetMode
Desktop::SetScreenMode
ServerApp::_DispatchMessage
ServerApp::_MessageLooper
...

See attached photo for detailled backtrace.

[mmlr]

I've seen this on another machine and it really is easily reproducible. I've added enough debug output to rule out that it comes from the place the stack trace would suggest. The buffer handling is fine, the free call is merely a victim of what's going on. My debug efforts showed that everything works as expected up to and including the call of fAccSetDisplayMode in AccelerantHWInterface::SetMode(). After that it seems like any access to libroot functions will fault (including the printf I added for debugging). I've tried to narrow it further down, but I can only suspect a side effect of the vm86 code to be the problem here. Since the code doesn't run through to update of the KDL framebuffer with the added debug output I wasn't able to gather more info just yet. I'll try to investigate further, but I don't really have a good overview of what should or should not happen within the vm86 code.