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Re: [PATCH v2] tracing: Make sure RCU is watching before calling a stack trace

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On Thu, 18 May 2017, Steven Rostedt wrote:

> 
> From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
> 
> As stack tracing now requires "rcu watching", force RCU to be watching when
> recording a stack trace.
> 
> Link: http://lkml.kernel.org/r/20170512172449.879684501@goodmis.org
> 
> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> ---
> 
> Changes since v1:
> 
>    My testing discovered that the stack trace can be called with
>    interrupts enabled, which is a no no to have when calling
>    rcu_irq_enter(). When interrupts are enabled, as with being in an
>    NMI, RCU will also be watching.

Would rcu_irq_enter_irqson() help then? This is what Petr used in a live 
patching handler.

Your solution works too, of course. Just asking if I am not missing 
something.

Thanks,
Miroslav

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[PATCH v2] tracing: Make sure RCU is watching before calling a  stack trace Steven Rostedt <rostedt@goodmis.org> - 2017-05-18 15:40 +0200
  Re: [PATCH v2] tracing: Make sure RCU is watching before calling a  stack trace Miroslav Benes <mbenes@suse.cz> - 2017-05-18 15:50 +0200
    Re: [PATCH v2] tracing: Make sure RCU is watching before calling a  stack trace Steven Rostedt <rostedt@goodmis.org> - 2017-05-18 16:10 +0200
      Re: [PATCH v2] tracing: Make sure RCU is watching before calling a  stack trace Miroslav Benes <mbenes@suse.cz> - 2017-05-18 20:20 +0200
  Re: [PATCH v2] tracing: Make sure RCU is watching before calling a  stack trace Steven Rostedt <rostedt@goodmis.org> - 2017-05-18 17:00 +0200
  Re: [PATCH v2] tracing: Make sure RCU is watching before calling a  stack trace "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-05-18 17:50 +0200
    Re: [PATCH v2] tracing: Make sure RCU is watching before calling a  stack trace Steven Rostedt <rostedt@goodmis.org> - 2017-05-18 18:40 +0200
      Re: [PATCH v2] tracing: Make sure RCU is watching before calling a  stack trace "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-05-18 20:50 +0200
        Re: [PATCH v2] tracing: Make sure RCU is watching before calling a  stack trace Steven Rostedt <rostedt@goodmis.org> - 2017-05-18 21:40 +0200
          Re: [PATCH v2] tracing: Make sure RCU is watching before calling a  stack trace "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-05-18 22:00 +0200

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