Re: [PATCH -tip v8 02/26] kprobes/x86: Allow to handle reentered kprobe on singlestepping

From: Steven Rostedt
Date: Fri Mar 21 2014 - 17:44:21 EST


On Wed, 05 Mar 2014 20:58:57 +0900
Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx> wrote:

> Since the NMI handlers(e.g. perf) can interrupt in the
> single stepping (or preparing the single stepping, do_debug
> etc.), we should consider a kprobe is hit in the NMI
> handler. Even in that case, the kprobe is allowed to be
> reentered as same as the kprobes hit in kprobe handlers
> (KPROBE_HIT_ACTIVE or KPROBE_HIT_SSDONE).
> The real issue will happen when a kprobe hit while another
> reentered kprobe is processing (KPROBE_REENTER), because
> we already consumed a saved-area for the previous kprobe.
>
> Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>

Reviewed-by: Steven Rostedt <rostedt@xxxxxxxxxxx>

-- Steve
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