Messages in this thread | | | From | Lai Jiangshan <> | Date | Tue, 26 May 2020 09:48:50 +0800 | Subject | Re: [RFC PATCH 0/5] x86/hw_breakpoint: protects more cpu entry data |
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On Mon, May 25, 2020 at 11:27 PM Peter Zijlstra <peterz@infradead.org> wrote: > > On Mon, May 25, 2020 at 02:50:57PM +0000, Lai Jiangshan wrote: > > Hello > > > > The patchset is based on (tag: entry-v9-the-rest, tglx-devel/x86/entry). > > And it is complement of 3ea11ac991d > > ("x86/hw_breakpoint: Prevent data breakpoints on cpu_entry_area"). > > > > After reading the code, we can see that more data needs to be protected > > against hw_breakpoint, otherwise it may cause > > dangerous/recursive/unwanted #DB. > > > > > > Lai Jiangshan (5): > > x86/hw_breakpoint: add within_area() to check data breakpoints > > x86/hw_breakpoint: Prevent data breakpoints on direct GDT > > x86/hw_breakpoint: Prevent data breakpoints on per_cpu cpu_tss_rw > > I think we can actually get rid of that #DB IST stack frobbing, also see > patches linked below.
Hi, Peter
I reviewed that patchset before. It is all what I want, but it still didn't remove IST-shifting. I remove it in V2.
> > > x86/hw_breakpoint: Prevent data breakpoints on user_pcid_flush_mask > > Should we disallow the full structure just to be sure?
Sure, just did it as you suggested, thanks!
> > > x86/hw_breakpoint: Prevent data breakpoints on debug_idt_table > > That's going away, see:
Yes, so I added a note in the patch, saying "Please drop this patch when Peter's work to remove debug_idt_table is merged."
I directly drop the patch in V2.
Thank you. Lai
> > https://lkml.kernel.org/r/20200522204738.645043059@infradead.org > > But yes, nice! >
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