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
Date: Thu, 4 May 2017 10:05:00 +0530 [thread overview]
Message-ID: <20170504043500.GA9733@naverao1-tp.localdomain> (raw)
In-Reply-To: <20170503155819.0cbd04e5@gandalf.local.home>
[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
next prev parent reply other threads:[~2017-05-04 4:36 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-04 4:36 [PATCH 0/8] powerpc: Various fixes and enhancements for kprobes and ftrace Naveen N. Rao
2017-05-04 4:36 ` [PATCH 1/8] powerpc/kprobes: Pause function_graph tracing during jprobes handling Naveen N. Rao
[not found] ` <20170503155819.0cbd04e5@gandalf.local.home>
2017-05-04 4:35 ` Naveen N. Rao [this message]
2017-05-04 4:36 ` [PATCH 2/8] powerpc/ftrace: Pass the correct stack pointer for DYNAMIC_FTRACE_WITH_REGS Naveen N. Rao
2017-05-04 4:36 ` [PATCH 3/8] powerpc/ftrace: Remove redundant saving of LR in ftrace[_graph]_caller Naveen N. Rao
2017-05-04 4:36 ` [PATCH 4/8] powerpc/kprobes_on_ftrace: Skip livepatch_handler() for jprobes Naveen N. Rao
2017-05-04 4:36 ` [PATCH 5/8] powerpc/ftrace: Eliminate duplicate stack setup for ftrace_graph_caller() Naveen N. Rao
2017-05-04 4:36 ` [PATCH 6/8] powerpc/ftrace: Add support for HAVE_FUNCTION_GRAPH_FP_TEST for -mprofile-kernel Naveen N. Rao
2017-05-04 4:36 ` [PATCH 7/8] powerpc/livepatch: Clarify location of mcount call site Naveen N. Rao
2017-05-04 4:36 ` [PATCH 8/8] powerpc/xmon: Disable function_graph tracing while in xmon Naveen N. Rao
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