Date: Wed, 2 Apr 2014 08:33:25 -0400
From: Steven Rostedt <rostedt@goodmis.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "H. Peter Anvin" <hpa@linux.intel.com>, Andi Kleen <ak@linux.intel.com>,
        Gleb Natapov <gleb@redhat.com>, Peter Anvin <hpa@zytor.com>,
        Jan Hubicka <hubicka@ucw.cz>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Ingo Molnar <mingo@kernel.org>, Paolo Bonzini <pbonzini@redhat.com>,
        Jaroslav Kysela <perex@perex.cz>,
        Peter Zijlstra <peterz@infradead.org>,
        Rusty Russell <rusty@rustcorp.com.au>,
        Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [GIT PULL] x86 LTO changes for v3.15
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On Tue, 1 Apr 2014 17:35:05 -0700
Linus Torvalds <torvalds@linux-foundation.org> wrote:

> On Tue, Apr 1, 2014 at 5:01 PM, Steven Rostedt <rostedt@goodmis.org> wrote:
> >
> > Why would they break tracing? I remember there was a issue with compat
> > calls, are these related to that?
> 
> They "break" tracing by being invisible to syscall tracing. As you
> really should know ;)
> 
> The syscall tracing feature depends on the wrappers that
> SYSCALL_DEFINEx() creates. See the SYSCALL_TRACE_ENTER_EVENT() etc
> crud in <linux/syscalls.h>
> 
> So there's no SYSCALL_METADATA for those system calls that weren't
> created with the proper SYSCALL_DEFINE() wrappers.
> 

Heh, I know that not having the SYSCALL_DEFINEx() wrappers means that
they wont be traced. I must have misunderstood Peter, as I thought he
meant if we added SYSCALL_DEFINEx(), that they would break tracing.

IIRC, the compat calls had some issues with the SYSCALL_DEFINE()
macros, and I was thinking theses functions would have some off the
wall issue as well.

Yeah, adding the SYSCALL_DEFINEx() macros around those functions would
be good for tracing as well.

Glad I understand you two now ;-)

I would have thought my jet lag would be over by now.

-- Steve
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