On 03/02/2012 05:11 PM, Linus Torvalds wrote: > On Fri, Mar 2, 2012 at 5:02 PM, H. Peter Anvin <hpa@xxxxxxxxx> wrote: >> >> Note that does mean we need a guard page after each and every >> discontiguous RAM range, not just the last one. Raising that issue >> since we have had serious bugs in that area in the past. > > Are you sure? I didn't think we even *mapped* things at that granularity. > > We only really need a guard page at the end of an actual end-of-ram > where we no longer have page tables and/or could hit device space. > Yes of course. Note that I'm currently pushing for mapping only RAM regions; we have a lot of bugs and workarounds related to mapping too much, and the answer to fixing that should be pretty obvious. > For robustness and actual deployment, I do think that yes, we do want > to make it an explicit rule. Definitely. Ideally those pages should be zeroed and mapped readonly. -hpa -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
