Mailing-List: contact cygwin-help AT cygwin DOT com; run by ezmlm List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-owner AT cygwin DOT com Mail-Followup-To: cygwin AT cygwin DOT com Delivered-To: mailing list cygwin AT cygwin DOT com X-Authentication-Warning: localhost.localdomain: ronald owned process doing -bs Date: Mon, 21 Jul 2003 18:49:31 +0200 (CEST) From: Ronald Landheer-Cieslak X-X-Sender: ronald AT localhost DOT localdomain To: cygwin AT cygwin DOT com Subject: Re: Crash in lynx In-Reply-To: <20030721154814.GQ1621@cygbert.vinschen.de> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Hi Corinna, > That's deep inside Windows. Looks like a problem with requesting info > from DNS, apparently. Yeah, but the weird thing is that this is not the error I get when I run it outside of the debugger. i.e., a STC shows that there is no problem with the call in question (gethostname) *unless* run from withing gdb. Here's the code: -- BEGIN STC -- #include int main( void ) { char buffer[2000]; gethostname( buffer, 2000 ); printf( "host name: %s\n", buffer ); return ( 0 ); } --- END STC --- When I save this as main.c and do a $ make main CFLAGS=-g gcc -g main.c -o main $ ./main host name: w2k-rlandheer $ gdb ./main ... (gdb) r Starting program: /home/RLandheer/test/gethostname/main.exe warning: HEAP[main.exe]: warning: Heap block at 00252DC0 modified at 00252DAA past requested size of ffffffe2 Program received signal SIGTRAP, Trace/breakpoint trap. 0x78477705 in ?? () This is regardless of whether I use canonical Cygwin 1.5.0 or current CVS Cygwin.The Lynx problem only occurs in current CVS Cygwin. (Hence, this is not the Lynx problem) An oddity: > warning: HEAP[main.exe]: > warning: Heap block at 00252DC0 modified at 00252DAA past requested size of ffffffe2 Anyways, this makes the Lynx problem very hard to debug, as I can't single-step through the code because that breaks the code.. Something interesting, though: gethostname is one of the auto-loaded functions which uses spiffy self-modifying assembler code. I have a feeling that might have something to do with this "can't step through code" problem, but that is just a WAG.. I'm going home, but if you have any ideas on how I can debug the Lynx problem without running into this SIGTRAP business I'm all ears. (i.e. I'll take a look tomorow during my coffee and/or lunchbreaks(s) rlc On Mon, 21 Jul 2003, Corinna Vinschen wrote: > On Mon, Jul 21, 2003 at 03:45:51PM +0200, Ronald Landheer-Cieslak wrote: > > A bit more info: I've just rebuilt cygwin1.dll and ran lynx under gdb. It > > crashed with a SIGTRAP. > > > > (gdb) bt > > #0 0x78477705 in ?? () > > #1 0x784aed7c in ?? () > > #2 0x78496695 in ?? () > > #3 0x784958fe in ?? () > > #4 0x78487111 in ?? () > > #5 0x784abeda in ?? () > > #6 0x770c1a2f in RPCRT4!NdrXmitOrRepAsMarshall () from /cygdrive/c/WINNT/system32/rpcrt4.dll > > #7 0x770d86b6 in RPCRT4!NdrClientInitialize () from /cygdrive/c/WINNT/system32/rpcrt4.dll > > #8 0x770d0d8b in RPCRT4!NdrConformantArrayMarshall () from /cygdrive/c/WINNT/system32/rpcrt4.dll > > #9 0x779788ac in DnsValidateUtf8Byte () from /cygdrive/c/WINNT/System32/dnsapi.dll > > #10 0x770c96cb in RpcStringFreeW () from /cygdrive/c/WINNT/system32/rpcrt4.dll > > #11 0x7712415e in RpcSsDontSerializeContext () from /cygdrive/c/WINNT/system32/rpcrt4.dll > > #12 0x779794bf in DnsRecordStringForType () from /cygdrive/c/WINNT/System32/dnsapi.dll > > #13 0x7797923a in DnsRecordStringForType () from /cygdrive/c/WINNT/System32/dnsapi.dll > > #14 0x77979a6f in DnsRecordCopyEx () from /cygdrive/c/WINNT/System32/dnsapi.dll > > #15 0x778334cf in RNR20!NSPStartup () from /cygdrive/c/WINNT/System32/RNR20.DLL > > That's deep inside Windows. Looks like a problem with requesting info > from DNS, apparently. > > Corinna > > -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/