Messages in this thread | | | Date | Tue, 28 Jul 2015 11:54:02 +0200 | From | Borislav Petkov <> | Subject | Re: [PATCH v2 3/3] x86/entry/64: Move #BP from IST to the IRQ stack |
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On Fri, Jul 24, 2015 at 10:57:06PM -0700, Andy Lutomirski wrote: > There's nothing IST-worthy about #BP/int3. We don't allow kprobes > in the small handful of places in the kernel that run at CPL0 with > an invalid stack, and 32-bit kernels have used normal interrupt > gates for #BP forever. > > Furthermore, we don't allow kprobes in places that have usergs while > in kernel mode, so "paranoid" is also unnecessary. > > Signed-off-by: Andy Lutomirski <luto@kernel.org> > --- > arch/x86/entry/entry_64.S | 2 +- > arch/x86/kernel/traps.c | 26 +++++++++++++------------- > 2 files changed, 14 insertions(+), 14 deletions(-)
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> @@ -494,7 +494,15 @@ dotraplinkage void notrace do_int3(struct pt_regs *regs, long error_code) > if (poke_int3_handler(regs)) > return; > > + /* > + * Use ist_enter despite the fact that we don't use an IST stack. > + * We can be called from a kprobe in non-CONTEXT_KERNEL kernel > + * mode or even during context tracking state changes. > + * > + * This means that we can't schedule. That's okay. > + */ > ist_enter(regs);
Let's rename that thing. Call it atomic_ctxt_enter or whatever...
-- Regards/Gruss, Boris.
ECO tip #101: Trim your mails when you reply. --
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