Question about madvise(DONTNEED) in glibc malloc

[Ondřej Bílka]

On Mon, Apr 15, 2013 at 08:48:24AM -0400, Rich Felker wrote:
> On Mon, Apr 15, 2013 at 02:35:04PM +0200, Ondřej Bílka wrote:
> > > > > > A SIGBUS makes using vrange out of question. We simply cannot ignore user generated SIGBUS.
> > > > > 
> > > > > Such SIGBUS would not happen unless the user accesses some freed memory,
> > > > > which he shouldn't be doing anyway.
> > > > 
> > > > When kill -BUS pid became illegal?
> > > 
> > > I don't understand how that relates to what we are talking about.  I've
> > > never said sending -BUS was illegal.  I've said that accessing freed
> > > memory is illegal.
> > 
> > Accessing freed memory is illegal but not only way how that SIGBUS could
> > happen. It could be SIGBUS from kill which is perfectly legal.
> 
> You misunderstand. glibc/malloc would not be _catching_ SIGBUS, so the
> fact that it's delivered when freed memory is accessed is irrelevant
> to applications unless they access freed memory (and then it's their
> fault they get it!). So I don't see what the problem is. This does not
> interfere with an application's use of SIGBUS whatsoever.
>
Sorry for noise, I misunderstand that we do not catch (which would be
problematic). 
> Rich