cygwin > 1.7.9: Segmentation faults / STATUS_STACK_OVERFLOW

[Manuel Wienand]

Hi,

I have the problem that I get a segmentation fault on the newer versions of the cygwin1.dll when debugging and a STATUS_STACK_OVERFLOW exception when running without debugger.
I did an update of my cygwin stuff on Monday, and I'm using the latest snapshot dll. I'm quite sure it has something to do with the dll, because I did clean and rebuild with newest
cygwin versions. Since this wasn't working, I got my old dll (from 29.03.2011) and it worked again.  I tried some other snapshot versions (up to 04.06.2011, since there are no old ones),
but none of them worked.

If I can get older snapshot versions, I might be able to track it down. But then again stack problems are hard to catch.
I compiled my code with -fstack-protector-all --param ssp-buffer-size=4, but this didn't help me so far (well, maybe I'm not using it right.).

Stacktrace of the first segmentation fault:
Thread [11] 0 (Suspended : Signal : SIGSEGV:Segmentation fault)          
_alloca() at ../../../libgcc/../gcc/config/i386/cygwin.asm:45 0x6116fd02	
__small_vswprintf() at /netrel/src/cygwin-snapshot-20120202-1/winsup/cygwin/smallprint.cc:369 0x610dbdfe	
0x0	

Another segmentation fault:
It can be triggered with my program after continuing when the firs tsegmentation fault.
I wasn't able to step into XCP_XmlResp_Ok. I checked the address of XCP_XmlResp_Ok, it stays the same from the program start.

Thread [19] 0 (Suspended : Signal : SIGSEGV:Segmentation fault)          
                _alloca() at /gnu/gcc/releases/respins/4.5.3-3/gcc4-4.5.3-3/src/gcc-4.5.3/libgcc/../gcc/config/i386/cygwin.asm:45 0x44ca42             
                XCP_XmlResp_Ok() at /cygdrive/c/.../XmlConfigParsing.c:2.278 0x409310   
                _fu82____stack_chk_guard() at /cygdrive/c/.../XmlConfigParsing.c:517 0x4051c2   
                _fu80____stack_chk_guard() at /cygdrive/c/.../XmlConfigParsing.c:166 0x404632   
                _fu434____stack_chk_guard() at /cygdrive/c/.../TcpIpServer.c:331 0x41843e           
                _fu427____stack_chk_guard() at /cygdrive/c/.../TcpIpServer.c:82 0x4179fb              
                pthread::thread_init_wrapper() at 0x610fa5d2                
                thread_wrapper() at 0x61085482            


Regards,
Manuel



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