Messages in this thread | | | Date | Mon, 25 May 2020 17:25:17 +0200 | From | Peter Zijlstra <> | Subject | Re: [RFC PATCH 0/5] x86/hw_breakpoint: protects more cpu entry data |
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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.
> x86/hw_breakpoint: Prevent data breakpoints on user_pcid_flush_mask
Should we disallow the full structure just to be sure?
> x86/hw_breakpoint: Prevent data breakpoints on debug_idt_table
That's going away, see:
https://lkml.kernel.org/r/20200522204738.645043059@infradead.org
But yes, nice!
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