Re: [PATCH] trace: Make trace_hwlat timestamp y2038 safe

From	Steven Rostedt <rostedt@goodmis.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH] trace: Make trace_hwlat timestamp y2038 safe
Date	2017-03-27 18:20 +0200
Message-ID	<tpFx8-2mb-25@gated-at.bofh.it> (permalink)
References	(3 earlier) <toTVw-1li-3@gated-at.bofh.it> <tpDEZ-QR-17@gated-at.bofh.it> <tpEhH-17e-15@gated-at.bofh.it> <tpEUp-1P8-13@gated-at.bofh.it> <tpEUq-1P8-21@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Mon, 27 Mar 2017 17:35:13 +0200
Arnd Bergmann <arnd@arndb.de> wrote:

> On Mon, Mar 27, 2017 at 5:30 PM, Steven Rostedt <rostedt@goodmis.org> wrote:
> > On Mon, 27 Mar 2017 16:53:09 +0200  
> >> We could probably introduce a %pts format string for timespec64
> >> and have that pretty-printed.  
> >
> > Hmm, probably don't want a %p as that suggests its a pointer, which it
> > should not be. Unless we pass in the address of the number.  
> 
> The special format strings that the kernel defines all start with %p and
> require passing by reference so we don't get a warning from gcc. We can't
> just make up new format strings otherwise, but we can create new meaning
> for special pointers as we do for struct resource and others.
> 

That's fine, but we need to be careful when it comes to tracing.
Passing in the address of a structure in the ring buffer may be fine,
but we need to make sure that an address pointing to something other
than the ring buffer is forbidden.

I'll need to update libtraceevent to handle such cases too.

-- Steve

Thread

[PATCH] trace: Make trace_hwlat timestamp y2038 safe Deepa Dinamani <deepa.kernel@gmail.com> - 2017-03-26 23:00 +0200
  Re: [PATCH] trace: Make trace_hwlat timestamp y2038 safe kbuild test robot <lkp@intel.com> - 2017-03-27 11:30 +0200
    Re: [PATCH] trace: Make trace_hwlat timestamp y2038 safe Arnd Bergmann <arnd@arndb.de> - 2017-03-27 12:00 +0200
      Re: [PATCH] trace: Make trace_hwlat timestamp y2038 safe Steven Rostedt <rostedt@goodmis.org> - 2017-03-27 16:40 +0200
        Re: [PATCH] trace: Make trace_hwlat timestamp y2038 safe Arnd Bergmann <arnd@arndb.de> - 2017-03-27 17:00 +0200
          Re: [PATCH] trace: Make trace_hwlat timestamp y2038 safe Arnd Bergmann <arnd@arndb.de> - 2017-03-27 17:40 +0200
            Re: [PATCH] trace: Make trace_hwlat timestamp y2038 safe Steven Rostedt <rostedt@goodmis.org> - 2017-03-27 18:20 +0200
          Re: [PATCH] trace: Make trace_hwlat timestamp y2038 safe Steven Rostedt <rostedt@goodmis.org> - 2017-03-27 17:40 +0200
          Re: [PATCH] trace: Make trace_hwlat timestamp y2038 safe Deepa Dinamani <deepa.kernel@gmail.com> - 2017-03-27 23:10 +0200
            Re: [PATCH] trace: Make trace_hwlat timestamp y2038 safe Arnd Bergmann <arnd@arndb.de> - 2017-03-28 09:30 +0200
  Re: [PATCH] trace: Make trace_hwlat timestamp y2038 safe kbuild test robot <lkp@intel.com> - 2017-03-27 12:10 +0200

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