Andy Lutomirski <[email protected]> writes: > On Mon, May 18, 2020 at 4:53 PM Thomas Gleixner <[email protected]> wrote: >> >> Andy Lutomirski <[email protected]> writes: >> > Actually, I revoke my ack. Can you make one of two changes: >> > >> > Option A: Add an assertion to run_on_irqstack to verify that irq_count >> > was -1 at the beginning? I suppose this also means you could just >> > explicitly write 0 instead of adding and subtracting. >> > >> > Option B: Make run_on_irqstack() just call the function on the current >> > stack if we're already on the irq stack. >> > >> > Right now, it's too easy to mess up and not verify the right >> > precondition before calling run_on_irqstack(). >> > >> > If you choose A, perhaps add a helper to do the if(irq_needs_irqstack) >> > dance so that users can just do: >> > >> > run_on_irqstack_if_needed(...); >> > >> > instead of checking everything themselves. >> >> I'll have a look tomorrow morning with brain awake. > > Also, reading more of the series, I suspect that asm_call_on_stack is > logically in the wrong section or that the noinstr stuff is otherwise > not quite right. I think that objtool should not accept > run_on_irqstack() from noinstr code. See followups on patch 10.
It's in entry.text which is non-instrumentable as well.
