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Date: Mon, 21 May 2012 14:50:46 -0600
From: Eric Blake <eblake AT redhat DOT com>
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Subject: Re: bash.exe.stackdump generated using cygwin 1.7.15
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On 05/21/2012 10:42 AM, Corinna Vinschen wrote:

>> The crash occurs after echo exited, so bash wakes up from the wait4
>> call.  However, the problem is that the crash does not occur in Cygwin,
>> but in bash itself.
>>
>>   147  350775 [main] bash 3548 wait4: 2320 =3D wait4(-1, 0x0, 0, 0x0)
>>   --- Process 3548, exception C0000005 at 00422B0A
>>
>> Eric, can you reproduce this and see where it happens?  I'm pretty sure
>> it's a bug in Cygwin, not in bash, but it would be interesting to learn
>> what bash did at the time the crash happened.
>=20
> Incidentally I built bash without -O2 option for better debugging and
> the problem vanished.  Then I built bash again with default optimization
> and the crash still didn't occur.  I built from the latest bash src
> package.4.1.10-4 using cygport.

Uggh.  This sounds familiar to another bash bug that I investigated some
time ago, where bash was abusing longjmp() and miscompiled under -O2 but
compiled correctly at -O0 due to the undefined behavior from that abuse,
but I just verified that my patch from back then is still present in my
latest build of bash for cygwin.  I'll have to find more time to look
into this.
https://lists.gnu.org/archive/html/bug-bash/2011-02/msg00060.html

--=20
Eric Blake   eblake AT redhat DOT com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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