Messages in this thread | | | Date | Mon, 25 Jun 2018 11:18:02 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: [PATCH v12 01/11] x86: text_poke() may access uninitialized struct pages |
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On Mon, 25 Jun 2018, Peter Zijlstra wrote: > On Mon, Jun 25, 2018 at 10:39:24AM +0200, Thomas Gleixner wrote: > > On Mon, 25 Jun 2018, Peter Zijlstra wrote: > > > I'm not entirely sure this is right.. Because not only do we need the > > > whole fixmap stuff working, we also need #DB and the IPI handlers set-up > > > and working. > > > > IPI? That's early UP boot why would you need an IPI? > > Because the way this is called is from __jump_label_transform() -> > text_poke_bp() -> text_poke() -> text_poke_early(). > > And if you look at text_poke_bp(), you'll note it relies on #DB and > on_each_cpu() IPIs.
on_each_cpu() resolves to a direct call on the current CPU and as there is no other CPU it does not matter. #DB might be a different story, haven't looked yet.
> Which is of course exactly the reason I avoided text_poke_bp() entirely > in the first place.
Fair enough.
Thanks,
tglx
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