On Mon, 23 Nov 2015 05:05:21 +0000 "Xie, Huawei" <huawei.xie at intel.com> wrote:
> On 11/23/2015 12:07 PM, Stephen Hemminger wrote: > > On Mon, 23 Nov 2015 03:46:31 +0000 > > "Xie, Huawei" <huawei.xie at intel.com> wrote: > > > >>> Why cannot we rely on the kernel zeroing the memory ? > >>> If that behavior were to change, then we can zero out the memory > >>> ourselves. > >> It is undocumented kernel behavior. My opinion is if not a big burden, > >> zero out the needed memory ourselves, otherwise resort to this kernel > >> behavior. > > Really, I think it is more an oversight of missing documentation, > > the kernel has always (and will continue) to zero out memory that is given > > to a process. If it didn't it would be a massive security hole. > Agree. I believe this behavior will not change in future. For the > security issue, kernel could also set all bits like to 1. Just wonder if > this is best practice and whether there are other user space programs > rely on this behavior. > Glibc almost certainly depends on this, because heap is grown by mmaping addtional memory.
