Re: [chuck-users] Debugging Segmentation fault: 11

On OS X, I found the following to be really handy: https://developer.apple.com/library/mac/documentation/Performance/Conceptual... so you can do things like: $ gdb chuck (gdb) set env MallocGuardEdges 1 (gdb) run Setting MallocGuardEdges, MallocScribble and MallocPreScribble might cause ChucK to get a segfault sooner. Then you print a backtrace by doing: (gbd) bt and send the results to Spencer for post mortem! HTH... - Rob On Tue Jan 27 2015 at 6:20:49 PM Spencer Salazar wrote:

+1 for gdb. If I were able to see a stack trace with function names (I think after it crashes in gdb, enter the 'backtrace' command) that would help a lot as far as pinpointing whatever in your ChucK code is triggering the crash.

spencer

On Tue, Jan 27, 2015 at 2:39 PM, Joel Matthys wrote:

...

Oh yeah! I had forgotten about ConsoleInput. (It's undocumented and I think it's generally considered archaic.) I know some early SLorK/PLorK pieces used Tcl/Tk GUIs outputting control numbers piped into ChucK. So I'm sure it's valid code, but I don't know how to debug it with GDB.

Joel

On 01/27/2015 04:33 PM, Gonzalo wrote:

...

This was a suggestion by Perry Cook, it's in chuck-users in a thread called "timestamps", Dec 14. The essence is:

ConsoleInput stdin; // gonna read from here stdin.prompt("") => now; // wait until something comes in while (stdin.more()) { stdin.getLine() => ... } // read input

(fully working code in his post)

I'll try your way to see if I can do this with gdb. Thanks!

On 28/01/2015 9:21 am, Joel Matthys wrote:

...

Hmm... I've never piped anything into ChucK like that before. How does ChucK access the timestamp?

Typically I would do something like that with an argument:

chuck wp.ck:`date +"%y%m%d-%T"`

and then access it in ChucK with me.arg(0) => string timestamp;

Joel

On 01/27/2015 03:27 PM, Gonzalo wrote:

...

Thanks Joel. One more hiccup: I start my chuck program with:

date +"%y%m%d-%T" | chuck wp.ck

(I need it to have a timestamp)

But I can't do that in gdb. I can disable the timestamp part in the code, but just checking to see if this is possible.

On 28/01/2015 8:01 am, Joel Matthys wrote:

...

I assume you're on Linux or OSX. (If it's Windows, I'm clueless.)

For me on Ubuntu I type:

$ *gdb chuck*

and then once it starts up and I get the (gdb) prompt I type:

(gdb) *run my_chuck_file.ck*

Of course GDB slows down your system, A LOT, but you can keep it running until it hits the segfault. The spew should (hopefully) point toward a specific place in the chuck code that is the problem. (Type q to exit gdb.) You might want to copy the error messages here for the devs to look into.

Joel

On 01/27/2015 02:53 PM, Gonzalo wrote:

> Never used gdb before, I'll read about this, but any pointers on how > to get started? > > > On 28/01/2015 7:39 am, Joel Matthys wrote: > >> It's hard to debug segfaults in the ChucK code itself. running gdb >> chuck >> might help narrow down the problem. >> >> Joel >> >> On 01/27/2015 02:31 PM, Gonzalo wrote: >> >>> Hi, >>> >>> On a project I'm working on, I sometimes get a "Segmentation fault: >>> 11" error, and the program crashes. But I can't figure out when it >>> happens, and cannot reproduce it. It's a big project, with many >>> components communicating via events, and I have no idea who's >>> triggering the problem. My question is how would you go about >>> debugging this? Any ideas what can be triggering it? It sounds very >>> generic... >>> >>> Probably unrelated, but just in case, I also got this (only once so >>> far): >>> >>> chuck(22226,0x7fff790ee310) malloc: *** error for object >>> 0x1028f3408: >>> incorrect checksum for freed object - object was probably modified >>> after being freed. >>> *** set a breakpoint in malloc_error_break to debug >>> Abort trap: 6 >>> >>> Thanks! >>> Gonzalo >>> _______________________________________________ >>> chuck-users mailing list >>> chuck-users@lists.cs.princeton.edu >>> https://lists.cs.princeton.edu/mailman/listinfo/chuck-users >>> >> >> _______________________________________________ >> chuck-users mailing list >> chuck-users@lists.cs.princeton.edu >> https://lists.cs.princeton.edu/mailman/listinfo/chuck-users >> >> _______________________________________________ > chuck-users mailing list > chuck-users@lists.cs.princeton.edu > https://lists.cs.princeton.edu/mailman/listinfo/chuck-users >

_______________________________________________ chuck-users mailing list chuck-users@lists.cs.princeton.edu https://lists.cs.princeton.edu/mailman/listinfo/chuck-users

_______________________________________________ chuck-users mailing list chuck-users@lists.cs.princeton.edu https://lists.cs.princeton.edu/mailman/listinfo/chuck-users

_______________________________________________ chuck-users mailing list chuck-users@lists.cs.princeton.edu https://lists.cs.princeton.edu/mailman/listinfo/chuck-users

_______________________________________________ chuck-users mailing list chuck-users@lists.cs.princeton.edu https://lists.cs.princeton.edu/mailman/listinfo/chuck-users

_______________________________________________ chuck-users mailing list chuck-users@lists.cs.princeton.edu https://lists.cs.princeton.edu/mailman/listinfo/chuck-users

-- Spencer Salazar Doctoral Candidate Center for Computer Research in Music and Acoustics Stanford University

spencer@ccrma.stanford.edu +1 831.277.4654 https://ccrma.stanford.edu/~spencer/

_______________________________________________ chuck-users mailing list chuck-users@lists.cs.princeton.edu https://lists.cs.princeton.edu/mailman/listinfo/chuck-users