Xorg crashing in pci_device_vgaarb_set_target

[Michel Dänzer]

On 13/10/17 08:59 AM, Peter Kasza wrote:
> On Tue, Oct 10, 2017 at 06:30:03PM +0000, Peter Kasza wrote:
>> On Tue, Oct 10, 2017 at 05:19:05PM +0000, Adam Jackson wrote:
>>> On Mon, 2017-10-09 at 13:07 +0200, Peter Kasza wrote:
>>>> Hi all,
>>>>
>>>> I'm getting itermittent crashes on a vfio enabled machine. I'm not
>>>> able to recreate it on purpose, but it seems to be occurring when
>>>> virtualbox VMs and Firefox are running.
>>>>
>>>> From the backtrace I suspect that some bogus parameter is passed to
>>>> the snprintf call, but other than that I'm not sure.
>>>>
>>>> The crash occurs in libpciaccess - pci_device_vgaarb_set_target. I
>>>> have the latest release installed (0.13.5).
>>>>
>>>> Program terminated with signal SIGSEGV, Segmentation fault.
>>>> #0  0x00007f17082667a3 in __GI__IO_default_xsputn () from /usr/lib/libc.so.6
>>>> [Current thread is 1 (Thread 0x7f170aa11940 (LWP 491))]
>>>> (gdb) bt
>>>> #0  0x00007f17082667a3 in __GI__IO_default_xsputn () at /usr/lib/libc.so.6
>>>> #1  0x00007f1708259b2d in __GI__IO_padn () at /usr/lib/libc.so.6
>>>> #2  0x00007f1708239938 in vfprintf () at /usr/lib/libc.so.6
>>>> #3  0x00007f17082efcbb in __vsnprintf_chk () at /usr/lib/libc.so.6
>>>> #4  0x00007f17082efbe5 in __snprintf_chk () at /usr/lib/libc.so.6
>>>> #5  0x00007f1709a966b8 in pci_device_vgaarb_set_target () at /usr/lib/libpciaccess.so.0
>>>> #6  0x00005616427d1fc8 in  ()
>>>
>>> Any chance you can (install debuginfo and) see the rest of this call
>>> trace? I suspect the value of 'dev' being passed into
>>> pci_device_vgaarb_set_target is just bogus, but without the call trace
>>> up through Xorg it's hard to see how that could happen.
>>>
>>> - ajax
>>
>> Hey,
>>
>> Thanks for the suggestion. I've compiled a debug version of X. I'll
>> reply back once I've reproduced the issue with more info.
> 
> Ok, it seems to have crashed again. I've attached the trace with debug
> symbols.

Looks like https://patchwork.freedesktop.org/patch/170077/ should fix this.


-- 
Earthling Michel Dänzer               |               http://www.amd.com
Libre software enthusiast             |             Mesa and X developer