[haiku-bugs] Re: [Haiku] #8068: A crash bring up the app_server in gdb when changing the screen resolution
- From: "mmlr" <trac@xxxxxxxxxxxx>
- Date: Tue, 22 Nov 2011 23:17:16 -0000
#8068: A crash bring up the app_server in gdb when changing the screen
resolution
----------------------------------+----------------------------
Reporter: oco | Owner: axeld
Type: bug | Status: new
Priority: normal | Milestone: R1
Component: Servers/app_server | Version: R1/Development
Resolution: | Keywords:
Blocked By: | Blocking:
Has a Patch: 0 | Platform: All
----------------------------------+----------------------------
Old description:
> Reproducible on a fresh install after few change of the screen resolution
> (less than five) on my laptop (Vesa mode)
>
> I use release r42926
>
> Overview of the backtrace :
>
> free
> MallocBuffer::MallocBuffer
> AccelerantHWInterface::SetMode
> Screen::SetMode
> Desktop::SetScreenMode
> ServerApp::_DispatchMessage
> ServerApp::_MessageLooper
> ...
>
> See attached photo for detailled backtrace.
New description:
Reproducible on a fresh install after few change of the screen resolution
(less than five) on my laptop (Vesa mode)
I use release r42926
Overview of the backtrace :
{{{
free
MallocBuffer::MallocBuffer
AccelerantHWInterface::SetMode
Screen::SetMode
Desktop::SetScreenMode
ServerApp::_DispatchMessage
ServerApp::_MessageLooper
...
}}}
See attached photo for detailled backtrace.
--
Comment (by 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.
--
Ticket URL: <http://dev.haiku-os.org/ticket/8068#comment:2>
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