[Qemu-devel] [Bug 696834] [NEW] FP exception reporting not working on NetBSD host

[Paul Goyette]

Public bug reported:

I recognize that NetBSD is not one of the officially supported host OS.
However, qemu 0.13.0 is available in the NetBSD pkgsrc collection, and
works quite well.  Well, with one exception (pun intended): It seems
that Floating Point exceptions don't get reported properly.

The following code-snippet demonstrates the problem:


volatile int flt_signal = 0;

static sigjmp_buf sigfpe_flt_env;
static void
sigfpe_flt_action(int signo, siginfo_t *info, void *ptr)
{
        flt_signal++;
}

void trigger(void)
{               
        struct sigaction sa;
        double d = strtod("0", NULL);
        
        if (sigsetjmp(sigfpe_flt_env, 0) == 0) {
                sa.sa_flags = SA_SIGINFO;
                sa.sa_sigaction = sigfpe_flt_action;
                sigemptyset(&sa.sa_mask);
                sigaction(SIGFPE, &sa, NULL);
                fpsetmask(FP_X_INV|FP_X_DZ|FP_X_OFL|FP_X_UFL|FP_X_IMP);
                printf("%g\n", 1 / d);
        }
        printf("FPE signal handler invoked %d times.\n");
}

** Affects: qemu
     Importance: Undecided
         Status: New

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https://bugs.launchpad.net/bugs/696834

Title:
  FP exception reporting not working on NetBSD host

Status in QEMU:
  New

Bug description:
  I recognize that NetBSD is not one of the officially supported host OS.  
However, qemu 0.13.0 is available in the NetBSD pkgsrc collection, and works 
quite well.  Well, with one exception (pun intended): It seems that Floating 
Point exceptions don't get reported properly.

The following code-snippet demonstrates the problem:


volatile int flt_signal = 0;

static sigjmp_buf sigfpe_flt_env;
static void
sigfpe_flt_action(int signo, siginfo_t *info, void *ptr)
{
        flt_signal++;
}

void trigger(void)
{               
        struct sigaction sa;
        double d = strtod("0", NULL);
        
        if (sigsetjmp(sigfpe_flt_env, 0) == 0) {
                sa.sa_flags = SA_SIGINFO;
                sa.sa_sigaction = sigfpe_flt_action;
                sigemptyset(&sa.sa_mask);
                sigaction(SIGFPE, &sa, NULL);
                fpsetmask(FP_X_INV|FP_X_DZ|FP_X_OFL|FP_X_UFL|FP_X_IMP);
                printf("%g\n", 1 / d);
        }
        printf("FPE signal handler invoked %d times.\n");
}