[GHC] #8371: ghci byte compiler + FFI crashes when used with embedded R

[Dominick Samperi]

Thanks! Turning off R's stack limit checks will not work. I tried this
and this leads to a segfault. Fortunately, your experiments led me
to a work-around: simply use the -fno-ghci-sandbox flag.

R is not thread-safe, and this flag tells ghci to run computations
in the main thread instead of forking.


On Sat, Sep 28, 2013 at 1:29 AM, GHC <ghc-devs at haskell.org> wrote:

> #8371: ghci byte compiler + FFI crashes when used with embedded R
> -------------------------------+----------------------------------
>         Reporter:  dsamperi    |            Owner:
>             Type:  bug         |           Status:  new
>         Priority:  normal      |        Milestone:
>        Component:  GHCi        |          Version:  7.6.3
>       Resolution:              |         Keywords:
> Operating System:  Linux       |     Architecture:  x86_64 (amd64)
>  Type of failure:  GHCi crash  |       Difficulty:  Unknown
>        Test Case:              |       Blocked By:
>         Blocking:              |  Related Tickets:
> -------------------------------+----------------------------------
>
> Comment (by rwbarton):
>
>  I can reproduce this without ghci, by putting a forkIO around the body of
>  main (and adding a threadDelay in the main thread).
>
>  It seems to just be an interaction between R's method for determining the
>  base address of the stack and the way pthread allocates stacks for new
>  threads. Try this C example program `pt.c`.
>
>  {{{
>  #include <stdio.h>
>  #include <unistd.h>
>  #include <pthread.h>
>
>  int Rf_initEmbeddedR(int argc, char **argv);
>
>  void *foo(void *blah)
>  {
>      char *args[] = {"pt", "--gui=none", "--silent", "--vanilla"};
>      int r;
>      setenv("R_HOME", "/usr/lib/R", 1);
>      r = Rf_initEmbeddedR(sizeof(args)/sizeof(args[0]), args);
>      printf("r = %d\n", r);
>  }
>
>  int main(void)
>  {
>      pthread_t tid;
>      pthread_create(&tid, NULL, foo, NULL);
>      while (1)
>          sleep(1);
>      return 0;
>  }
>  }}}
>
>  {{{
>  rwbarton at adjunction:/tmp$ gcc -o pt pt.c  -lpthread -lR
>  rwbarton at adjunction:/tmp$ ./pt
>  Error: C stack usage is too close to the limit
>  Error: C stack usage is too close to the limit
>  r = 1
>  }}}
>
>  It would probably be best to just disable R's stack limit checks, if
>  possible.
>
> --
> Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8371#comment:6>
> GHC <http://www.haskell.org/ghc/>
> The Glasgow Haskell Compiler
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.haskell.org/pipermail/ghc-devs/attachments/20130928/2a9c4495/attachment.htm>