Re: [PATCH 21/22] xfs: %pF is only for function pointers

From: Scott Wood <scottwood@freescale.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Dave Chinner <david@fromorbit.com>, <trivial@kernel.org>,
	<linux-kernel@vger.kernel.org>, <xfs@oss.sgi.com>
Subject: Re: [PATCH 21/22] xfs: %pF is only for function pointers
Date: Mon, 31 Aug 2015 14:58:24 -0500	[thread overview]
Message-ID: <1441051104.4966.41.camel@freescale.com> (raw)
In-Reply-To: <20150831154521.1c9353b6@gandalf.local.home>

On Mon, 2015-08-31 at 15:45 -0400, Steven Rostedt wrote:
> On Mon, 31 Aug 2015 14:24:25 -0500
> Scott Wood <scottwood@freescale.com> wrote:
>  
> > > Can you please look into why this change broke the tracing output
> > > on x86-64 - if there is no obvious/easy fix for it, then I'm simply
> > > going to revert it because having the tracing work correctly on
> > > x86-64 is far more important to us than ppc64 or ia64....
> > 
> > It looks like the cause is that TP_printk() is not really printk() -- it 
> > actually passes the format to userspace which has its own, not 100% 
> > compatible implementation pretty_print() in tools/lib/traceevent/event-
> > parse.c.  %pf in that function behaves like %ps in the kernel, and %ps is 
> > absent.
> > 
> 
> We can fix that with adding %ps to the traceevent library.

I wasn't sure if this would be considered a stable ABI issue, as it's not 
about the events themselves, but about the event mechanism.

-Scott