* Closing on the CR2 leak bug
@ 2014-03-04 22:34 H. Peter Anvin
2014-03-04 23:41 ` Steven Rostedt
0 siblings, 1 reply; 4+ messages in thread
From: H. Peter Anvin @ 2014-03-04 22:34 UTC (permalink / raw)
To: Vince Weaver, Peter Zijlstra, Ingo Molnar, Thomas Gleixner,
Steven Rostedt, Paul Mackerras, Arnaldo Carvalho de Melo,
Seiji Aguchi
Cc: Linux Kernel Mailing List
So we need to get something into x86/urgent for the CR2 bug.
It seems like a no-brainer to do the hoisting patch, for which I prefer
the version proposed by Jiri Olsa which reads %cr2 and then passes it to
__do_page_fault() in a GPR:
http://lkml.kernel.org/r/20140228160526.GD1133@krava.brq.redhat.com
As fart as I can tell this should fix Vince's problem as well.
Anyone who objects to this? Otherwise I will put it in tip:x86/urgent
tomorrow.
Do we need any more refinements this late in the -rc cycle?
-hpa
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Closing on the CR2 leak bug
2014-03-04 22:34 Closing on the CR2 leak bug H. Peter Anvin
@ 2014-03-04 23:41 ` Steven Rostedt
2014-03-04 23:44 ` H. Peter Anvin
0 siblings, 1 reply; 4+ messages in thread
From: Steven Rostedt @ 2014-03-04 23:41 UTC (permalink / raw)
To: H. Peter Anvin
Cc: Vince Weaver, Peter Zijlstra, Ingo Molnar, Thomas Gleixner,
Paul Mackerras, Arnaldo Carvalho de Melo, Seiji Aguchi,
Linux Kernel Mailing List
On Tue, 04 Mar 2014 14:34:00 -0800
"H. Peter Anvin" <hpa@zytor.com> wrote:
> So we need to get something into x86/urgent for the CR2 bug.
>
> It seems like a no-brainer to do the hoisting patch, for which I prefer
> the version proposed by Jiri Olsa which reads %cr2 and then passes it to
> __do_page_fault() in a GPR:
>
> http://lkml.kernel.org/r/20140228160526.GD1133@krava.brq.redhat.com
>
> As fart as I can tell this should fix Vince's problem as well.
>
> Anyone who objects to this? Otherwise I will put it in tip:x86/urgent
> tomorrow.
>
> Do we need any more refinements this late in the -rc cycle?
>
The only other issue is if perf traces from function context and traces
the trace_do_page_fault() call. But other than that, sure, take Jiri's
patch.
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Please also add the reported/tested-by from Vince Weaver and add a
Link: to the other thread, as it got pretty detailed there too.
-- Steve
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Closing on the CR2 leak bug
2014-03-04 23:41 ` Steven Rostedt
@ 2014-03-04 23:44 ` H. Peter Anvin
2014-03-05 0:00 ` Steven Rostedt
0 siblings, 1 reply; 4+ messages in thread
From: H. Peter Anvin @ 2014-03-04 23:44 UTC (permalink / raw)
To: Steven Rostedt
Cc: Vince Weaver, Peter Zijlstra, Ingo Molnar, Thomas Gleixner,
Paul Mackerras, Arnaldo Carvalho de Melo, Seiji Aguchi,
Linux Kernel Mailing List
On 03/04/2014 03:41 PM, Steven Rostedt wrote:
>
> The only other issue is if perf traces from function context and traces
> the trace_do_page_fault() call. But other than that, sure, take Jiri's
> patch.
>
Is there a known codepath on which that can happen?
-hpa
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Closing on the CR2 leak bug
2014-03-04 23:44 ` H. Peter Anvin
@ 2014-03-05 0:00 ` Steven Rostedt
0 siblings, 0 replies; 4+ messages in thread
From: Steven Rostedt @ 2014-03-05 0:00 UTC (permalink / raw)
To: H. Peter Anvin
Cc: Vince Weaver, Peter Zijlstra, Ingo Molnar, Thomas Gleixner,
Paul Mackerras, Arnaldo Carvalho de Melo, Seiji Aguchi,
Linux Kernel Mailing List
On Tue, 04 Mar 2014 15:44:26 -0800
"H. Peter Anvin" <hpa@zytor.com> wrote:
> On 03/04/2014 03:41 PM, Steven Rostedt wrote:
> >
> > The only other issue is if perf traces from function context and traces
> > the trace_do_page_fault() call. But other than that, sure, take Jiri's
> > patch.
> >
>
> Is there a known codepath on which that can happen?
I'm not sure. Jiri, is there a way we can trace userspace from
the ftrace function event? What would be the command to try? I know you
had a patch to prevent it, but is it currently possible?
-- Steve
^ permalink raw reply [flat|nested] 4+ messages in thread
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2014-03-04 22:34 Closing on the CR2 leak bug H. Peter Anvin
2014-03-04 23:41 ` Steven Rostedt
2014-03-04 23:44 ` H. Peter Anvin
2014-03-05 0:00 ` Steven Rostedt
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