Re: Dealing with the NMI mess

From: Steven Rostedt
Date: Fri Jul 24 2015 - 10:31:38 EST


On Fri, 24 Jul 2015 15:21:28 +0200
Willy Tarreau <w@xxxxxx> wrote:

> My understanding is that by using RET we can't set the RF flag and #DB

But the RF flag is only set for instruction (executing) breakpoints. It
is not set for data (RW) ones.

-- Steve

> will immediately strike again when the operation is attempted again. Thus
> we have to completely disable the breakpoints on leaving after the first
> one strikes, resulting in some userland breakpoints being missed. Maybe
> it can be accepted as a limitation when perf is running. I don't know if
> the output of perf is that relevant when a debugger is present BTW.
>
> Willy

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