From: Josh Poimboeuf <jpoimboe@redhat.com>
To: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Steven Rostedt <rostedt@goodmis.org>,
Paul Menzel <pmenzel@molgen.mpg.de>, Len Brown <lenb@kernel.org>,
linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org,
Ingo Molnar <mingo@kernel.org>
Subject: Re: [PATCH] acpi: fix incompatibility with mcount-based function graph tracing
Date: Mon, 27 Mar 2017 09:08:43 -0500 [thread overview]
Message-ID: <20170327140843.fx5y32rnc3mqiyke@treble> (raw)
In-Reply-To: <5766300.HtmE7iLEgV@aspire.rjw.lan>
On Sat, Mar 25, 2017 at 02:20:11PM +0100, Rafael J. Wysocki wrote:
> On Friday, March 24, 2017 02:41:14 PM Steven Rostedt wrote:
> > On Fri, 24 Mar 2017 13:12:54 -0500
> > Josh Poimboeuf <jpoimboe@redhat.com> wrote:
> >
> >
> > > Instead I was able to "fix" it by ignoring ftrace calls in real mode:
> > >
> > > -----
> > > index 8f3d9cf..5c0d0c6 100644
> > > --- a/arch/x86/kernel/ftrace.c
> > > +++ b/arch/x86/kernel/ftrace.c
> > > @@ -983,6 +983,9 @@ void prepare_ftrace_return(unsigned long self_addr, unsigned long *parent,
> > > unsigned long return_hooker = (unsigned long)
> > > &return_to_handler;
> > >
> > > + if (__builtin_return_address(0) < TASK_SIZE_MAX)
> > > + return;
> > > +
> > > if (unlikely(ftrace_graph_is_dead()))
> > > return;
> > > ---------------
> > >
> > > I'm not sure what the best fix should really be. A few ideas off the
> > > top of my head:
> > >
> > > - A real mode check similar to the above (except it should probably be
> > > more precise)
> >
> > The real mode check hack may be good enough for now. Make sure that
> > it's commented well.
>
> Agreed.
Just to clarify, there are two bugs related to function graph tracing
and suspend/resume. The original patch in this thread (which removes
'-Os' from the acpi Makefile) is still needed.
--
Josh
next prev parent reply other threads:[~2017-03-27 14:09 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-16 13:56 [PATCH] acpi: fix incompatibility with mcount-based function graph tracing Josh Poimboeuf
2017-03-16 14:41 ` Steven Rostedt
2017-03-21 20:44 ` Paul Menzel
2017-03-22 0:04 ` Paul Menzel
2017-03-24 18:12 ` Josh Poimboeuf
2017-03-24 18:41 ` Steven Rostedt
2017-03-25 13:20 ` Rafael J. Wysocki
2017-03-27 14:08 ` Josh Poimboeuf [this message]
2017-03-27 14:54 ` [PATCH] ftrace/x86: fix x86-32 triple fault with graph tracing and suspend-to-ram Josh Poimboeuf
2017-03-27 15:01 ` Paul Menzel
2017-03-27 15:20 ` [PATCH v2] " Josh Poimboeuf
2017-03-27 15:24 ` [PATCH] " Steven Rostedt
2017-03-28 9:51 ` Paul Menzel
2017-03-28 15:39 ` Steven Rostedt
2017-03-28 15:55 ` Josh Poimboeuf
2017-03-28 21:12 ` Rafael J. Wysocki
2017-03-28 21:42 ` Josh Poimboeuf
2017-03-28 21:47 ` Rafael J. Wysocki
2017-03-27 16:59 ` [PATCH] acpi: fix incompatibility with mcount-based function graph tracing Rafael J. Wysocki
2017-03-26 20:57 [PATCH] trace: Make trace_hwlat timestamp y2038 safe Deepa Dinamani
2017-03-27 9:25 ` kbuild test robot
2017-03-27 9:55 ` Arnd Bergmann
2017-03-27 14:28 ` Steven Rostedt
2017-03-27 14:53 ` Arnd Bergmann
2017-03-27 15:30 ` Steven Rostedt
2017-03-27 15:35 ` Arnd Bergmann
2017-03-27 16:11 ` Steven Rostedt
2017-03-27 21:02 ` Deepa Dinamani
2017-03-28 7:26 ` Arnd Bergmann
2017-03-27 10:04 ` kbuild test robot
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