On Mon, 20 Nov 2017, Andy Lutomirski wrote: > On Fri, Nov 10, 2017 at 11:31 AM, Dave Hansen > <dave.hansen@xxxxxxxxxxxxxxx> wrote: > > > > From: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> > > > > The IDT is another structure which the CPU references via a > > virtual address. It also obviously needs these to handle an > > interrupt in userspace, so these need to be mapped into the user > > copy of the page tables. > > Why would the debug IDT ever be used in user mode? IIRC it's a total > turd related to avoiding crap nesting inside NMI. Or am I wrong? No. It's called from the TRACE_IRQS macros in the ASM entry code and from do_nmi(). > If it *is* used in user mode, then we have a bug and it should be in > the IDT to avoid address leaks just like the normal IDT. It's not so this can go away. Good catch. Thanks, tglx -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
