Re: [chuck-users] chuck under gdb?

Tom: Good guess, but that doesn't seem to be the problem here. I found what tickled the bug and have worked around it, but I have no insights as the the cause: * In the crashing version, I was loading up a bunch of SndBuf objects (doing sndbuf.read(...)) early in the startup phase. * When I stopped pre-loading _all_ sndbufs, no crash. * When I pre-loaded _any_one_ sndbuf, crash (but randomly once in a dozen times executing the fun void a() code, etc). * When I moved the calls to sndbuf.read() to "load on demand just before using it", no crash. I need to point out that the place where the ChucK VM crashed had *nothing* to do with SndBufs -- lexically and temporally, the "fun void a()" code was far removed from any SndBuf code. The only thing that I can imagine is that ChucK has a thread internal to the VM which it uses for lazy reads, and it's somehow corrupting the stack. (???) Unfortunately, this is part of a large-ish real- time performance system. If someone really wants to debug this, contact me and I'll do what I can to trim it down to a minimum failing example. - Rob On 24 May 2009, at 05:37, Tom Lieber wrote:

On Sun, May 24, 2009 at 1:32 AM, Robert Poor wrote:

...

I've recompiled chuck with -g and it just gets stranger: with a construct along the lines of:

fun void a() { <<< "in a before b" >>>; b(); <<< "in a after b" >>>; }

fun void b() { <<< "entering b" >>>; ...do some stuff... <<< "exiting b" >>>; }

There are no yields() that would let another process run in-between the call to b and returning to a, but it *sometimes* crashes after the return, so I see the equivalent of:

"in a before b" "entering in b" "exiting in b" [crash]

I'm seeing a "KERN_INVALID_ADDRESS" at a non-zero address, thrown from inside Chuck_Instr_Reg_Push_Imm::execute()

I'm at a real loss how to tackle this one. Its part of a large body of code, so excerpting it down to a minimal example would be tough. Absent any suggestions from the Chuck wizards out there, I'm tempted to simply re-write my code in a different way and hope it makes a difference. But that's not my favorite approach.

Suggestions more than welcome.

Well, the only non-bus-error of ways to crash ChucK I'm familiar with is to use variables before their definition in a way the compiler doesn't catch. Liiike:

fun void a() { b(); } a(); int v[1]; fun void b() { <<< v[0] >>>; }

-- Tom Lieber http://AllTom.com/ _______________________________________________ chuck-users mailing list chuck-users@lists.cs.princeton.edu https://lists.cs.princeton.edu/mailman/listinfo/chuck-users

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