Re: OpenBSD hangs / crashes with Suduku

[Riccardo Mottola]

Hi,

indeed. Just to be sure, I used a platform where SUdoku and put a 
breakpoint. I confirm that the exception is always thrown. Terrible 
code, I have the urge to rewrite it properly... it looks like roughly 
like tail-recursion.

In any case it is no excuse for exceptions not working on openbsd :)

Riccardo

Fred Kiefer wrote:
> As Sebastian already pointed out not the exception is the problem 
> here, but the way we currently implement it.
>
> The exception itself is part of the algorithm of that application. 
> It's a sort of structured long jump, when a solution is found 
> somewhere deep down in the recursion it jumps back to the top of the 
> stack. Not a very nice way to do this, but at least it pretends not to 
> be a goto :-)
>
> On 22.06.2011 11:04, Riccardo Mottola wrote:
> > Hi,
> >
> > I am able to reproduce the problems Sebastian has on my own OpenBSD/x86
> > box. I get this problem only on OpenBSD. I use gcc and its standard
> > runtime. The same combination appears to work fine on NetBSD or Linux.
> >
> > The problem happens with "New" inside Sudoku (latest version from CVS of
> > GAP).
> >
> > The happening is:
> >
> > 1) Sudoku is run normally (not in GDB). Sudokup.apps remains eternally
> > at 99% of CPU usage and hangs
> > 2) If run inside GDB, I get the same broken crash of Sebastian:
> > #0 0x0d8ea287 in NSCountFrames () at NSDebug.m:1009
> > #1 0x0d8edf19 in GSPrivateStackAddresses () at NSDebug.m:1112
> > #2 0x0d902f5f in -[GSStackTrace init] (self=0x7d17a2e8, _cmd=0x2d8e89e8)
> > at NSException.m:605
> > #3 0x0d951942 in +[NSObject new] (self=0x2d8cfac0, _cmd=0x2d8cfb40)
> > at NSObject.m:1281
> > #4 0x0d90387c in -[NSException raise] (self=0x7d17a168, _cmd=0x2d8cfba8)
> > at NSException.m:960
> > #5 0x0d902e04 in +[NSException raise:format:arguments:] 
> > (self=0x2d8cf9c0,
> > _cmd=0x2d8cfb90, name=0x3c00615c, format=0x3c006150,
> > argList=0xcfbf0a80 "ðR÷\213h¾O'\027\003") at NSException.m:849
> > #6 0x0d903cf3 in +[NSException raise:format:] (self=0x2d8cf9c0,
> > _cmd=0x3c0060f8, name=0x3c00615c, format=0x3c006150) at 
> > NSException.m:835
> > #7 0x1c0070ad in -[Sudoku doFind:] (self=0x7e509008, _cmd=0x3c0060d8,
> > seen=0x87e36fc8) at Sudoku.m:457
> > #8 0x1c006fbe in -[Sudoku doFind:] (self=0x7e509008, _cmd=0x3c0060d8,
> > seen=0x87e36fc8) at Sudoku.m:524
> > #9 0x1c006fbe in -[Sudoku doFind:] (self=0x7e509008, _cmd=0x3c0060d8,
> > seen=0x87e36fc8) at Sudoku.m:524
> > #10 0x1c006fbe in -[Sudoku doFind:] (self=0x7e509008, _cmd=0x3c0060d8,
> > seen=0x87e36fc8) at Sudoku.m:524
> > #11 0x1c006fbe in -[Sudoku doFind:] (self=0x7e509008, _cmd=0x3c0060d8,
> > seen=0x87e36fc8) at Sudoku.m:524
> >
> >
> > I can also put a breakpoint in NSException raise and get the similar
> > output:
> >
> > #0 -[NSException raise] (self=0x7c139488, _cmd=0x2835eba8)
> > at NSException.m:956
> > #1 0x08391e04 in +[NSException raise:format:arguments:] 
> > (self=0x2835e9c0,
> > _cmd=0x2835eb90, name=0x3c006174, format=0x3c006168,
> > argList=0xcfbf01f0 "0÷\234\201h®\210&\027\003") at NSException.m:849
> > #2 0x08392cf3 in +[NSException raise:format:] (self=0x2835e9c0,
> > _cmd=0x3c0060f8, name=0x3c006174, format=0x3c006168) at 
> > NSException.m:835
> > #3 0x1c006f80 in -[Sudoku doFind:] (self=0x84f0a008, _cmd=0x3c0060d8,
> > seen=0x87651648) at Sudoku.m:452
> > #4 0x1c006fbe in -[Sudoku doFind:] (self=0x84f0a008, _cmd=0x3c0060d8,
> > seen=0x87651648) at Sudoku.m:524
> > #5 0x1c006fbe in -[Sudoku doFind:] (self=0x84f0a008, _cmd=0x3c0060d8,
> > seen=0x87651648) at Sudoku.m:524
> > #6 0x1c006fbe in -[Sudoku doFind:] (self=0x84f0a008, _cmd=0x3c0060d8,
> > seen=0x87651648) at Sudoku.m:524
> > #7 0x1c006fbe in -[Sudoku doFind:] (self=0x84f0a008, _cmd=0x3c0060d8,
> > seen=0x87651648) at Sudoku.m:524
> > #8 0x1c006fbe in -[Sudoku doFind:] (self=0x84f0a008, _cmd=0x3c0060d8,
> > seen=0x87651648) at Sudoku.m:524
> > #9 0x1c006fbe in -[Sudoku doFind:] (self=0x84f0a008, _cmd=0x3c0060d8,
> > seen=0x87651648) at Sudoku.m:524
> > #10 0x1c006fbe in -[Sudoku doFind:] (self=0x84f0a008, _cmd=0x3c0060d8,
> > seen=0x87651648) at Sudoku.m:524
> >
> > the exception is raised from line 452;
> > [NSException raise:EX_COMPLETE format:EX_COMPLETE_FMT];
> >
> > line 524:
> > [self doFind:seen];
> >
> > (which means indeed recursion)
> >
> >
> > Seen as this it looks like a code problem, but if it happens only on
> > OpenBSD I think of some kind of corruption. "placed" gets initialized
> > before...
> >
> > Thanks,
> > Riccardo
> >
> >
> > and seq is an object instance variable, which makes me think of
> > corruption in the object.
>
>
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