Segmentation fault (core dumped)

[nm1002]

when I run fuzzball, after entering fuzzball -linux-syscalls -fuzz-start-addr 0x080485af -symbolic-word 0xbfffcf4c=n simple -- ./simple 42 in the terminal,I encountered segmentation fault(core dumped).I found that the "flush out" statement in the "exec_run_common.ml" file caused this problem,but I don't know how to solve it.

[smcc]

This problem sounds a bit mysterious and low-level, so it has the best
chance of being fixed if it's reproducible. Using one of the supplied
examples helps with that, but giving more details about how you
compiled FuzzBALL would also be helpful. If you're mostly using the
standard packages of a well-known Linux distribution, the distribution
version would be the quickest shorthand.

The function call "flush stdout" isn't one that you would usually
expect to cause a segfault. OCaml's memory safety catches most of the
problems that would be segfaults in a C program, and flushing standard
output (similar to the C "fflush(stdout)") shouldn't involve many
dynamically-allocated pointers. What evidence led you to conclude that
the call to flush is the cause of the problem? If you were lead to
that based on running your test under GDB, it would be helpful to see
more details like a full stack backtrace, the faulting instruction,
and the values of its operands.

I mentioned I'm a bit skeptical of the flush being the true problem,
but you could test that hypothesis by commenting out this call to
flush and repeating your testing. The flushing shouldn't change
FuzzBALL's behavior when it's executing normally: it just affects the
order in which messages are printed including messages that might be
missed if they are still buffered at the point of a crash.