Re: [ANNOUNCEMENT] Updated: xorg-server-1.17.1-3

[Ken Brown <kbrown@cornell.edu>]

On 5/1/2015 2:19 PM, Jon TURNEY wrote:
> On 01/05/2015 13:43, Ken Brown wrote:
>> On 5/1/2015 7:56 AM, Jon TURNEY wrote:
>>> On 30/04/2015 23:19, Ken Brown wrote:
>>>> On 4/29/2015 1:26 PM, Jon TURNEY wrote:
>>>>>
>>>>> The following packages have been updated in the Cygwin distribution:
>>>>>
>>>>> *** xorg-server-*1.17.1-3
>>>>
>>>> I'm finding, on three different 64-bit Cygwin systems, that the server
>>>> dies shortly after starting.  I'm attaching XWin.0.log from one of
>>>> them.
>>>>   The log from a 32-bit Cygwin install on the same machine starts the
>>>> same but then continues with
>>>>
>>>> [440201.140] winPointerWarpCursor - Discarding first warp: 640 512
>>>> [440201.140] (--) 8 mouse buttons found
>>>> [440201.140] (--) Setting autorepeat to delay=500, rate=31
>>>> [...]
>>>>
>>>> The problem goes away if I revert to 1.17.1-2.  Let me know if there's
>>>> further information that I can provide.
>>>
>>> That is rather mysterious and disappointing.  I can't reproduce this.
>>>
>>> Does this occur if you run XWin directly?
>>
>> Yes.
>>
>>> If so, could you perhaps upload a strace somewhere, please?
>>
>> http://sanibeltranquility.com/cygwin/xwin.trace.xz
>
> Thanks.
>
> This ends with ...
>
> --- Process 2996, exception c0000005 at 0000000180155C82
>
> and...
>
> $ addr2line -e /usr/lib/debug/usr/bin/cygwin1.dbg 0x0000000180155C82
> /usr/src/debug/cygwin-2.0.1-1/winsup/cygwin/malloc.cc:4753
>
> ... which is somewhere inside free().
>
> I don't quite understand why cygwin's exception processing doesn't then
> catch that exception and raise a SIGSEGV.
>
> However, I did a bit more staring at the changes in 1.17.1-3 and I did
> find a nasty bug in some code which uses the heap.  I've uploaded a
> snapshot [1] with a possible fix, please test that if you can.

That fixes it.  Thanks.

Ken


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