linux-kernel - kprobes vs __ex

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Message-ID: <20170223183002.GD6557@twins.programming.kicks-ass.net>
Date:   Thu, 23 Feb 2017 19:30:02 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     mhiramat@...nel.org
Cc:     Borislav Petkov <bp@...en8.de>, linux-kernel@...r.kernel.org,
        Ingo Molnar <mingo@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>
Subject: kprobes vs __ex_table[]

Hi Masami,

I just wondered what would happen if I put a probe on an instruction
that was listed in __ex_table[] or __bug_table[].

And it looks like it will happily do that. It will then run the
instruction out-of-line, and when said instruction traps, the
instruction address will not match the one listed in either __ex_table[]
or __bug_table[] and badness will happen.

If kprobes does indeed not check this, we should probably fix it, if it
does do check this, could you point me to it?