Sender:	rich AT phekda DOT freeserve DOT co DOT uk
Message-ID:	<3D396624.53AE0ADE@phekda.freeserve.co.uk>
Date:	Sat, 20 Jul 2002 14:31:16 +0100
From:	Richard Dawe <rich AT phekda DOT freeserve DOT co DOT uk>
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To:	DJGPP workers <djgpp-workers AT delorie DOT com>
Subject:	Re: Emacs CVS and Windows NT 4
References:	<3D395BD7 DOT 943F9BA4 AT phekda DOT freeserve DOT co DOT uk>
Reply-To:	djgpp-workers AT delorie DOT com

Hello.

Richard Dawe wrote:
> I've just been debugging the crashes I get when I try to use Emacs, built
> from a month-or-so-old CVS, under Windows NT 4. It looks like an sbrk
> problem to me. Looking at the crashes, I see the following set of calls to
> sbrk from __default_morecore.
> 
> __default_morecore called with an increment of:
> 
> 0 -> OK
> 36 -> OK
> 290696 -> bombs out, when I step over sbrk call
> 
> The last call to __default_morecore arises from a call to
> adjust_frame_glyphs_for_frame_redisplay.
[snip]

As I've said in another mail, it was crashing on a cli instruction in
brk_common. I discovered that I wasn't running a "pure" copy of CVS. So I've
reverted the changes to src/libc/crt0 and rebuilt. Now it looks like the crash
is in crt0.S here:

	movw	$0x0900, %ax					/* disable interrupts */
	int	$0x31
	pushl	%eax

	LCALL(sbrk16_api_ofs) <--- CRASHES HERE

	setc	%dl						/* Save carry */

	popl	%eax					/* restore interrupts */
	int	$0x31

This is with the same patten of calls to __default_morecore. I get backtraces
like this, when I hit the crash in brk_common under gdb:

"Exiting due to signal SIGTRAP
Debug at eip=00000012
eax=005e0901 ebx=0000005e ecx=005e0000 edx=005b8000 esi=00590176 edi=01761da0
ebp=0056ad28 esp=0056acf0 program=C:\DEVELOP\EMACS\BIN\EMACS.EXE
cs: sel=02cf  base=000221c0  limit=0000026f
ds: sel=02af  base=03440000  limit=005bffff
es: sel=02af  base=03440000  limit=005bffff
fs: sel=025f  base=0001e1a0  limit=00003fff
gs: sel=02d7  base=00000000  limit=0010ffff
ss: sel=02af  base=03440000  limit=005bffff
App stack: [0056b054..004eb054]  Exceptn stack: [002524b8..00250578]


Program exited with code 0377."

Actually for a while the program got further in allocating memory with a
pattern of calls to __default_morecore like this:

    0, 36, 290696, 0, -172032, 0, 196608, 0, 0, 139264 <- bombs out

It seems to be sensitive to how much keyboard activity there is. I haven't
worked out the relation between keypresses and crashes yet.

Has anyone got any ideas what's going on? Is there any more information I can
provide?

Thanks, bye, Rich =]

-- 
Richard Dawe [ http://www.phekda.freeserve.co.uk/richdawe/ ]

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