On Sat, Feb 16, 2008 at 02:48:17PM +0100, Thomas Gleixner wrote: > On Sat, 16 Feb 2008, Heiko Carstens wrote: > > > > Well, NULL pointer dereferencing is supposed to fail, isn't it ? > > > > I wasn't sure that this is true for all architectures, but... > > It's an requirement for futex support.
To be more precise: dereferencing alone won't cause an exception for NULL pointers on s390. Only writes will do so. That is very architecture specific since we cannot unmap page 0, it contains per-cpu data -- like exception pointers and all such stuff that the cpu needs. Just in case there is any code that relies on the fact that also reads via a NULL pointer are supposed to failed. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
