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Date:	Wed, 12 Sep 2001 11:25:11 -0400
From:	Christopher Faylor <cgf AT redhat DOT com>
To:	cygwin-developers AT cygwin DOT com
Subject:	Re: Got Make to SEGV in gdb, but don't know what to do about it
Message-ID:	<20010912112511.A21005@redhat.com>
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On Wed, Sep 12, 2001 at 10:35:24AM -0400, Jonathan Kamens wrote:
>I duplicated the Make SEGV problem and got gdb to pop up in the
>running Make process, but I don't see anything in any of the threads
>that gives me any clues about how to proceed.  Any suggestions?
>
>  Program received signal SIGSEGV, Segmentation fault.
>  [Switching to thread 1036.0x4e0]
>  (gdb) thread apply all where
>
>  Thread 4 (thread 1036.0x4e0):
>  #0  0x77f9eeaa in _cygheap_start ()
>  #1  0x77ea8983 in _cygheap_start ()
>  #2  0x77e837cd in _cygheap_start ()
>
>  Thread 3 (thread 1036.0x49c):
>  #0  0x77f820f0 in _cygheap_start ()
>  #1  0x77e8366e in _cygheap_start ()
>  #2  0x77e860c6 in _cygheap_start ()
>  #3  0x61004f7a in thread_stub (arg=0x6109ca38)
>      at ../../../../src/winsup/cygwin/debug.cc:97
>  #4  0x77e837cd in _cygheap_start ()
>
>  Thread 2 (thread 1036.0x44c):
>  #0  0x77f820f0 in _cygheap_start ()
>  #1  0x77e8366e in _cygheap_start ()
>  #2  0x77e860c6 in _cygheap_start ()
>  #3  0x61004f7a in thread_stub (arg=0x6109ca38)
>      at ../../../../src/winsup/cygwin/debug.cc:97
>  #4  0x77e837cd in _cygheap_start ()
>
>  Thread 1 (thread 1036.0x3d0):
>  #0  0x40d5ef in _size_of_heap_reserve__ ()
>  Cannot access memory at address 0x100000
>  #0  0x77f9eeaa in _cygheap_start ()
>  (gdb) 

This is the same symptom that we saw before.  It looks like it's stopped
in make and you don't have a debugging version of make.

Possibly, the stack is corrupted since thread 1 should have much more
information than that.

I don't have any insight to offer.  If you want to inspect the stack,
you can do a

x/40x $esp

That will show the first 40 words.  There will probably be recognizable
cygwin addresses on the stack but I don't know how much information you'd
be able to glean after the fact.

I set a make -j2 running all night with no errors so apparently I can't
duplicate the problem anymore.

cgf

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