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Date: Fri, 21 May 2010 18:23:55 +0200
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Subject: Large binaries crash with exception C0000005
From: Magnus Reftel <magnus DOT reftel AT gmail DOT com>
To: cygwin AT cygwin DOT com
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Hi,

A crash in a bunch of clang binaries that used to work got me chasing
down what appears to be a bug in Cygwin with regards to large exe
files. A binary I built as a test case that was 263615179 bytes was
OK, but when I added one more byte to a global array, it was pushed to
263615691 bytes, and failed with the same crash as clang (the clang
binaries, BTW, are between 350 and 360 MB).

I'm not sure when the clang binaries last worked (I would guess about
three weeks ago), but now they all terminate with error code 127, and
strace reports the following:

$ strace big.exe
--- Process 10852, exception C0000005 at 1003B392
--- Process 10852, exception C0000005 at 7C9666C6

I've tried with GDB, but it's not being very helpful:

$ gdb big.exe
GNU gdb 6.8.0.20080328-cvs (cygwin-special)
Copyright (C) 2008 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "i686-pc-cygwin"...
(gdb) run
Starting program: /c/Documents and Settings/qrefmag/src/big_exe/big.exe
[New thread 11048.0x20d8]

Program exited with code 030000000005.
You can't do that without a process to debug.
(gdb)

Setting CYGWIN='error_start:C:\cygwin\bin\dumper.exe' does not produce
any core dump or stack trace, either with a Windows command window or
with mintty.

I have not modified the clang exe files since they worked. I'm not
sure whether I upgraded Cygwin since between the time I last had them
working and when they failed, but it would be likely. Anyway, I have
now upgraded so I'm at DLL version 1.7.5. The crash is still here.

Random observation: Stephen Morton reported something similar in
http://sourceware.org/ml/cygwin/2010-05/msg00157.html . Could this be
related?

Best Regards
Magnus Reftel

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