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Date:   Mon, 15 Jun 2020 17:55:13 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     tglx@linutronix.de
Cc:     x86@kernel.org, elver@google.com, paulmck@kernel.org,
        kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org,
        will@kernel.org, dvyukov@google.com, glider@google.com,
        andreyknvl@google.com
Subject: Re: [PATCH 2/9] rcu: Fixup noinstr warnings
Message-ID: <20200615155513.GG2554@hirez.programming.kicks-ass.net>
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 <20200603114051.896465666@infradead.org>
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On Mon, Jun 15, 2020 at 05:49:05PM +0200, Peter Zijlstra wrote:
> @@ -983,13 +993,17 @@ noinstr void rcu_nmi_enter(void)
>  		if (!in_nmi())
>  			rcu_cleanup_after_idle();
>  
> +		instrumentation_begin();
> +		// instrumentation for the noinstr rcu_dynticks_curr_cpu_in_eqs()
> +		instrument_atomic_read(&rdp->dynticks, sizeof(rdp->dynticks));
> +		// instrumentation for the noinstr rcu_dynticks_eqs_exit()
> +		instrument_atomic_write(&rdp->dynticks, sizeof(rdp->dynticks));
> +
>  		incby = 1;
>  	} else if (!in_nmi()) {
>  		instrumentation_begin();
>  		rcu_irq_enter_check_tick();
> -		instrumentation_end();
>  	}
> -	instrumentation_begin();
>  	trace_rcu_dyntick(incby == 1 ? TPS("Endirq") : TPS("++="),
>  			  rdp->dynticks_nmi_nesting,
>  			  rdp->dynticks_nmi_nesting + incby, atomic_read(&rdp->dynticks));

Oh, that's lost a possible instrumentation_begin() :/ But weirdly
objtool didn't complain about that... Let me poke at that.