trouble trapping SEGV on 2.6.11.2 & 2.6.12-rc4

["Clifford T. Matthews" <ctm@ardi.com>]

The included program dies with a SEGV under 2.6.11.2 and 2.6.12-rc4.
It doesn't die under 2.4.25.  I compiled the kernels myself.  The
distribution is Fedora Core release 3, with glibc 2.3.5.

I don't have any earlier 2.6 kernels to test it on, so I have no idea
when this bug first appeared.

I only skim LKML through fa.linux.kernel, so please CC me on any reply
that I should see.

--Cliff Matthews <ctm@ardi.com>
+1 505 363 5754 Cell

#include <stdio.h>
#include <unistd.h>
#include <sys/mman.h>
#include <stdbool.h>
#include <assert.h>
#include <setjmp.h>
#include <signal.h>

static jmp_buf segv_return;

static void
segv_handler (int signum_ignored __attribute__((unused)))
{
  longjmp (segv_return, 1);
}

int
main (void)
{
  volatile char *volatile addr;
  volatile int n_failures;

  addr = (void *) 0x10000L;
  n_failures = 0;

  signal (SIGSEGV, segv_handler);
  if (setjmp (segv_return) != 0)
    ++n_failures;
  else
    *addr;

  printf ("n_failures = %d\n", n_failures);

  if (setjmp (segv_return) != 0)
    ++n_failures;
  else
    *addr;

  printf ("n_failures = %d\n", n_failures);

  return 0;
}