From: Paul Steckler <steck@stecksoft.com>
To: caml-list@yquem.inria.fr
Subject: Re: Segfaults with Dynlink with OCaml 3.11
Date: Wed, 25 Aug 2010 14:00:30 +1000 [thread overview]
Message-ID: <AANLkTinxtK-ScwAHUyZ7-UVPtKVFtu0FYFrjo5UraiZo@mail.gmail.com> (raw)
In-Reply-To: <AANLkTin6GWH+Csz4QLVbfs4M7=+zD8PCNgfKwMDfT9_v@mail.gmail.com>
On Mon, Aug 23, 2010 at 8:57 PM, Paul Steckler <steck@stecksoft.com> wrote:
> I'm getting segmentation faults when using dynamically linked native
> code in 64-bit OCaml 3.11 running on Linux (Fedora 12 x64).
Many thanks to all who gave useful advice on tracking down this problem.
We have three chunks of C code we're calling, so we went through those
and audited our use of the FFI conventions. Indeed, we found a number
of instances where we used return instead of CAMLreturn, and so on.
But the segfaults were occurring before our C code was ever called,
and before any code was called in OCaml packages we use that are
linked against C code, such as sqlite3. So the segfaults occurred
even after patching our C code.
Today, I found the culprit. Here's the pattern:
dynamically load .cmxs file
query list mutated by .cmxs file (* no problem *)
Gc.set { (Gc.get()) with Gc.minor_heap_size = ...};
Gc.set { (Gc.get()) with Gc.major_heap_increment = ... };
query mutated list (* segfault! *)
If I move the Gc.set's to the program initialization code, before the
loading of dynamic code, no segfaults occur.
Is this expected behavior? I don't see caveats about interaction with
the garbage collector in the documentation for the Dynlink module, nor
anything about dynamic linking in the Gc module documentation.
-- Paul
next prev parent reply other threads:[~2010-08-25 4:00 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-23 10:57 Paul Steckler
2010-08-23 11:06 ` [Caml-list] " Stéphane Glondu
2010-08-23 11:47 ` Paul Steckler
2010-08-23 12:05 ` Mark Shinwell
2010-08-23 12:12 ` Paul Steckler
2010-08-23 12:15 ` Daniel Bünzli
2010-08-23 12:28 ` Anil Madhavapeddy
2010-08-23 15:48 ` Stéphane Glondu
2010-08-25 4:00 ` Paul Steckler [this message]
2010-09-03 14:59 ` [Caml-list] " Damien Doligez
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