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Re: [PATCH -tip tracing/kprobes 1/6] kprobes/x86: Call BUG() when reentering probe into KPROBES_HIT_SS
- From: Ananth N Mavinakayanahalli <ananth at in dot ibm dot com>
- To: Masami Hiramatsu <mhiramat at redhat dot com>
- Cc: Frederic Weisbecker <fweisbec at gmail dot com>, Ingo Molnar <mingo at elte dot hu>, lkml<linux-kernel at vger dot kernel dot org>, systemtap<systemtap at sources dot redhat dot com>, DLE<dle-develop at lists dot sourceforge dot net>
- Date: Fri, 28 Aug 2009 10:08:32 +0530
- Subject: Re: [PATCH -tip tracing/kprobes 1/6] kprobes/x86: Call BUG() when reentering probe into KPROBES_HIT_SS
- References: <20090827152539.GE6058@nowhere> <20090827172258.8246.61889.stgit@localhost.localdomain>
- Reply-to: ananth at in dot ibm dot com
On Thu, Aug 27, 2009 at 01:22:58PM -0400, Masami Hiramatsu wrote:
> Call BUG() when a probe have been hit on the way of kprobe processing path,
> because that kind of probes are currently unrecoverable (recovering it will
> cause an infinit loop and stack overflow).
>
> The original code seems to assume that it will be caused by an int3 which
> another subsystem inserted on out-of-line singlestep buffer if the hitting
> probe is same as current probe. However, in that case, int3-hitting-address
> is on the out-of-line buffer and should be different from first (current)
> int3 address.
> Thus, I decided to remove the code.
>
> I also removes arch_disarm_kprobe() because it will involve other stuffs
> in text_poke().
>
> Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
> Cc: Frederic Weisbecker <fweisbec@gmail.com>
> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
> Cc: Ingo Molnar <mingo@elte.hu>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>