On Thu, Jun 25, 2009 at 02:13:00PM +0100, Ralf Baechle wrote:
> >> int main(void)
> >> {
> >> int *deadbeef = (int *) 0xdeadbeef;
> >> signal(SIGBUS, SIG_IGN);
> >> printf("*deadbeef == %d\n", *deadbeef);
> >> return 0;
> >> }
> >>
> >> If any fatal exception is ignored, the program should be killed
> >> if that exception happens. 100% CPU is not a useful response.
> >>
> > It's not a useful program, so what did you expect? One might argue
> > that it would be more useful or correct to have the kernel advance the
> > PC to not endlessly repeat the doomed load, but ignoring SIG_IGN and
> > silently killing the thread violates the signal API as I've always
> > understood it.
>
> It's not a useful program but valid as a test case. However I agree with
> your interpretation of signal semantics but I'll have to round up a copy
> of the relevant standard documents; I have vague memories about some small
> print for cases like this.
I found this in IRIX 6.5 documentation:
Caution: Signals raised by the instruction stream, SIGILL, SIGEMT, SIGBUS,
and SIGSEGV, will cause infinite loops if their handler returns,
or the action is set to SIG_IGN.
Ralf
