[Python-Dev] stack check on Unix: any suggestions?

Skip Montanaro skip@mojam.com (Skip Montanaro)
Sat, 2 Sep 2000 23:25:49 -0500 (CDT)

    Thomas> In one test I did, it crashed in int_print, the print function
    Thomas> for int objects, which did 'fprintf(fp, "%ld", v->ival);'.  The
    Thomas> actual SEGV arrived inside fprintf's internals. v->ival was a
    Thomas> valid integer (though a high one) and the problem was not
    Thomas> derefrencing 'v'. 'fp' was stderr, according to its _fileno
    Thomas> member.

I get something similar.  The script conks out after 4491 calls (this with a
threaded interpreter).  It segfaults in _IO_vfprintf trying to print 4492 to
stdout.  All arguments to _IO_vfprintf appear valid (though I'm not quite
sure how to print the third, va_list, argument).

When I configure --without-threads, the script runs much longer, making it
past 18068.  It conks out in the same spot, however, trying to print 18069.
The fact that it occurs in the same place with and without threads (the
addresses of the two different _IO_vfprintf functions are different, which
implies different stdio libraries are active in the threading and
non-threading versions as Thomas said), suggests to me that the problem may
simply be that in the threading case each thread (even the main thread) is
limited to a much smaller stack.  Perhaps I'm seeing what I'm supposed to
see.  If the two versions were to crap out for different reasons, I doubt
I'd see them failing in the same place.