Messages in this thread |  | | | Subject | Re: [Bug 10489] Kprobe smoke test lockdep warning | | From | Peter Zijlstra <> | | Date | Tue, 22 Apr 2008 18:05:58 +0200 |
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On Tue, 2008-04-22 at 11:25 -0400, Masami Hiramatsu wrote: > Peter Zijlstra wrote: > > On Tue, 2008-04-22 at 15:09 +0200, Peter Zijlstra wrote: > >> On Mon, 2008-04-21 at 18:54 -0400, Masami Hiramatsu wrote: > >>> Thank you for reporting. > >>> > >>> Actually, kprobes tries to fixup thread's flags in post_kprobe_handler > >>> (which is called from kprobe_exceptions_notify) by > >>> trace_hardirqs_fixup_flags(pt_regs->flags). However, even the irq flag > >>> is set in pt_regs->flags, true hardirq is still off until returning > >>> from do_debug. Thus, lockdep assumes that hardirq is off without annotation. > > > > Ah, can you clarrify? pt_regs->flags will only be set when returning to > > the original trap site? in that case we should not need a lockdep > > annotation I guess, unless its allowed and exptected for the int3 site > > to change IRQ state. > > As far as I took a look at the lockdep, your suggestion is correct. > post_kprobe_handler should not set a lockdep annotation, because > processor's IF is not changed yet in that time.
That much was clear; but when _will_ it be changed?
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