emacs-nox hogs CPU if backgrounded during compile

[Ryan Johnson]

On 27/08/2013 8:06 AM, Ken Brown wrote:
> On 8/27/2013 4:28 AM, Ryan Johnson wrote:
>> On 17/08/2013 2:41 PM, Ryan Johnson wrote:
>>> Hi all,
>>>
>>> The following STC causes emacs-nox to peg a CPU indefinitely. Emacs
>>> remains responsive, but C-c C-k doesn't kill the compile; you have to
>>> exit emacs to remove the "Compiling" status. Killing the buffer or
>>> starting a new compile offers to kill the offending process, but 
>>> doesn't.
>>>
>>> Attaching gdb shows an endless loop inside
>>> kernelbase.dll!RaiseException, but provides no other clues that I
>>> could see.
>>>
>>> 1. emacs-nox -Q
>>> 2. M-x compile
>>> 3. C-a C-k sleep 1; echo hi
>>> 4. ^Z (before the sleep finishes)
>>> 5. fg (after the sleep finishes)
>>>
>>> I don't know if this is related to limited pipe buffering, but I don't
>>> think so: it has always worked in the past, and the the 3-4 bytes
>>> required to buffer up "hi\n" is hardly onerous.
>>>
>>> $ uname -a
>>> CYGWIN_NT-6.1 ryan-laptop-v02 1.7.24(0.269/5/3) 2013-08-15 11:59
>>> x86_64 Cygwin
>>>
>>> $ cygcheck -cd
>>> bash                      4.1.11-1
>>> cygwin                    1.7.24-1
>>> emacs                     24.3-5
>>> mintty                    1.2-beta1-1
> > Ping... is anyone else at least able to reproduce this?
>
> I can reproduce this on both x86 and x86_64, even without the "echo hi". 
Update: the problem only occurs if output arrives while emacs is 
stopped. So, "echo hi; sleep 5; echo ho" will not cause the problem if 
you ^Z/fg during the gap.

Ryan

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