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Date: Thu, 4 May 2017 10:05:00 +0530
From: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>,
 Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>,
 Masami Hiramatsu <mhiramat@kernel.org>,
 Anton Blanchard <anton@samba.org>, linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH 1/8] powerpc/kprobes: Pause function_graph tracing during
 jprobes handling
References: <cover.1493831558.git.naveen.n.rao@linux.vnet.ibm.com>
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[Copying linuxppc-dev list which I missed cc'ing initially]

On 2017/05/03 03:58PM, Steven Rostedt wrote:
> On Wed,  3 May 2017 23:43:41 +0530
> "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com> wrote:
> 
> > This fixes a crash when function_graph and jprobes are used together.
> > This is essentially commit 237d28db036e ("ftrace/jprobes/x86: Fix
> > conflict between jprobes and function graph tracing"), but for powerpc.
> > 
> > Jprobes breaks function_graph tracing since the jprobe hook needs to use
> > jprobe_return(), which never returns back to the hook, but instead to
> > the original jprobe'd function. The solution is to momentarily pause
> > function_graph tracing before invoking the jprobe hook and re-enable it
> > when returning back to the original jprobe'd function.
> 
> I wonder if any of this code could be made arch agnostic?

I don't see a way to do that as the jprobe handlers are all 
arch-specific.

> 
> Anyway, Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Thanks,
- Naveen