[racket] why a segfault on the command line, but not in DrRacket?

From: Pierpaolo Bernardi (olopierpa at gmail.com)
Date: Tue Dec 30 15:06:38 EST 2014

Just for excluding any possibility of user error: do you use any
unsafe features?

On Tue, Dec 30, 2014 at 8:43 PM, Matthew Butterick <mb at mbtype.com> wrote:
> No, it's all Racket libraries.
>
> OTOH I may be the one causing the memory-management problems. The issues are
> arising in my typesetting program, which passes around some large data
> structures as function inputs. By "large" I mean a list of 10e5 to 10e6
> structs, each with its own hashtable. Perhaps this is imprudent. It
> certainly makes the GC huff and puff (about 25-30% of my running time is GC)
>
> OTOOH, it does seem to be a command-line peculiarity, because I haven't
> found a similar limit for DrRacket yet. For instance, I just typeset a file
> with 1.5M characters, resulting in a ~600 page PDF, and it ran fine.
>
> When I tried running on the command line with this input, I got a different
> error than before (and within a couple seconds of starting the program):
>
> Seg fault (internal error during gc) at 0x10aac0000
> Bus error: 10 (core dumped)
>
>
>
>
> On Tue, Dec 30, 2014 at 11:09 AM, Matthew Flatt <mflatt at cs.utah.edu> wrote:
>>
>> Does your program use any foreign libraries? That behavior sounds typical
>> of memory-management problems.
>>
>> > On Dec 30, 2014, at 11:47 AM, Matthew Butterick <mb at mbtype.com> wrote:
>> >
>> > I have a program that consistently works in DrRacket regardless of input
>> > size.
>> >
>> > But on the command line, once input exceeds a certain threshold, the
>> > program consistently dies with a "Segmentation fault: 11 (core dumped)"
>> > error (though it works with smaller files). I'm invoking `racket` without
>> > any special flags, like so:
>> >
>> > racket main.rkt
>> >
>> > I know which line of my program is triggering the segfault. But since
>> > the error is related to the input size and the use of command-line Racket, I
>> > think I ought to look elsewhere for the cause.
>> >
>> > Are there particular command-line flags that can be helpful in
>> > diagnosing segfaults? Is a segfault like this typically due to running out
>> > of memory?
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>
>
>
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