Messages in this thread | | | Date | Mon, 20 Nov 2017 21:54:13 +0100 (CET) | From | Thomas Gleixner <> | Subject | Re: [PATCH 17/30] x86, kaiser: map debug IDT tables |
| |
On Mon, 20 Nov 2017, Andy Lutomirski wrote:
> On Fri, Nov 10, 2017 at 11:31 AM, Dave Hansen > <dave.hansen@linux.intel.com> wrote: > > > > From: Dave Hansen <dave.hansen@linux.intel.com> > > > > 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
| |