Messages in this thread | | | Date | Fri, 8 May 2020 14:45:56 +0200 | From | Peter Zijlstra <> | Subject | Re: [patch V4 part 4 15/24] x86/db: Split out dr6/7 handling |
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On Fri, May 08, 2020 at 01:58:30PM +0200, Thomas Gleixner wrote: > Peter Zijlstra <peterz@infradead.org> writes: > >> > +static __always_inline void debug_enter(unsigned long *dr6, unsigned long *dr7) > >> > +{ > >> > + /* > >> > + * Disable breakpoints during exception handling; recursive exceptions > >> > + * are exceedingly 'fun'. > >> > + * > >> > + * Since this function is NOKPROBE, and that also applies to > >> > + * HW_BREAKPOINT_X, we can't hit a breakpoint before this (XXX except a > >> > + * HW_BREAKPOINT_W on our stack) > >> > + * > >> > + * Entry text is excluded for HW_BP_X and cpu_entry_area, which > >> > + * includes the entry stack is excluded for everything. > >> > + */ > >> > + get_debugreg(*dr7, 6); > >> > >> Do you mean get_debugreg(*dr7, 7); ? > > > > Shees, I have to go buy a new stack of brown paper bags at this rate, > > don't I :/ > > Not only you, but it's also amazing that the selftests didn't catch > that.
I don't think the selftests try and set hardware breakpoints in the kernel.
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