On Tue, 10 May 2011 00:14:42 -0300, David Bremner <brem...@debian.org> wrote:
> On Mon, 9 May 2011 06:56:48 -0600, Matthew Flatt <mfl...@cs.utah.edu> wrote:
> > Maybe someone decided that SIGSEGV is the right signal after all for an
> > mprotect() violation (which Rackets catches as a write barrier) instead
> > of SIGBUS.
>
> I suppose there is a good reason not to catch both signals?
>
> David
I don't claim to understand all the implications yet, but the following
patch seems to work, i.e. catching both SIGSEGV and SIGBUS with the same
handler.
>From 748f1dd0b6d387bc0577075e56afde3958c08f86 Mon Sep 17 00:00:00 2001
From: David Bremner <brem...@debian.org>
Date: Tue, 10 May 2011 22:50:04 -0300
Subject: [PATCH] on GNU/kFreeBSD, catch both SIGBUS and SIGSEGV from mprotect
---
src/racket/gc2/sighand.c | 11 ++++++++++-
1 files changed, 10 insertions(+), 1 deletions(-)
diff --git a/src/racket/gc2/sighand.c b/src/racket/gc2/sighand.c
index 5b4b991..87e02aa 100644
--- a/src/racket/gc2/sighand.c
+++ b/src/racket/gc2/sighand.c
@@ -134,10 +134,13 @@ void fault_handler(int sn, siginfo_t *si, void *ctx)
abort();
}
# define NEED_SIGACTION
-# if (defined(__FreeBSD__) && (__FreeBSD_version < 700000)) || defined(__FreeBSD_kernel__)
+# if (defined(__FreeBSD__) && (__FreeBSD_version < 700000))
# define USE_SIGACTON_SIGNAL_KIND SIGBUS
# else
# define USE_SIGACTON_SIGNAL_KIND SIGSEGV
+# ifdef __FreeBSD_kernel__
+# define ALSO_CATCH_SIGBUS
+# endif
# endif
#endif
@@ -230,6 +233,9 @@ static void initialize_signal_handler(GCTYPE *gc)
act.sa_flags |= SA_ONSTACK;
# endif
sigaction(USE_SIGACTON_SIGNAL_KIND, &act, &oact);
+# ifdef ALSO_CATCH_SIGBUS
+ sigaction(SIGBUS, &act, &oact);
+# endif
}
# endif
# ifdef NEED_SIGWIN
@@ -263,6 +269,9 @@ static void remove_signal_handler(GCTYPE *gc)
sigemptyset(&act.sa_mask);
act.sa_flags = SA_SIGINFO;
sigaction(USE_SIGACTON_SIGNAL_KIND, &act, &oact);
+# ifdef ALSO_CATCH_SIGBUS
+ sigaction(SIGBUS, &act, &oact);
+# endif
}
# endif
# ifdef NEED_SIGWIN
--
1.7.4.4
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