[64bit] emacs is unable to call subprocesses if display-time-mode is set

Ken Brown kbrown@cornell.edu
Wed Apr 3 18:00:00 GMT 2013

On 4/3/2013 10:05 AM, Corinna Vinschen wrote:
> On Apr  3 09:49, Ken Brown wrote:
>> On 4/3/2013 7:41 AM, Corinna Vinschen wrote:
>>> On Apr  2 18:57, Ken Brown wrote:
>>>> How did you figure out that the crash occurs in cmalloc?  I tried
>>>> addr2line, but it gave me no information:
>>>> $ addr2line -e /bin/cygwin1.dll 1800429F4
>>>> ??:?
>>> Are you sure the stackdump is from the same version of the Cygwin
>>> DLL you're running now?
>> I didn't get a stackdump.  I was relying on the following line from
>> the strace output:
>>    Process 4928, exception c0000005 at 00000001800429F4
>> I just reproduced that today, with the same address, so there's no
>> question of the DLL version.
> Hmm.  Did you install the cygwin-debuginfo package?  If all else
> fails, try `addr2line -e /usr/lib/debug/usr/bin/cygwin1.dbg'.  I get
>    $ $ addr2line -e /usr/lib/debug/usr/bin/cygwin1.dbg 1800429F4
>    /usr/src/debug/cygwin-1.7.18-15/winsup/cygwin/cygheap.cc:298

Ah, that works.  I thought addr2line was supposed to know where to find 

> I can reproduce the issue but it's tricky to debug.  The exception
> occurs in the forked process and GDB can't follow fork on Cygwin.
> Btw., can you create an emacs which is built without optimization
> and non-stripped this would simplify debuigging a bit...

It was already built without optimization.  I'm working on building a 
non-stripped version, but cygport isn't cooperating.  If you put 
"RESTRICT=strip" into the .cygport file, then cygport doesn't package 
the sources.  So you get a binary with debugging symbols, but you don't 
get the corresponding sources.

I'll send Yaakov a patch, but in the meantime I'm working around this. 
It shouldn't be long.


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