linux-kernel - Re: [PATCH] lockdep: call time_hardirqs_off after clearing hardirqs

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Message-ID: <20170313230442.17705320@grimm.local.home>
Date:   Mon, 13 Mar 2017 23:04:42 -0400
From:   Steven Rostedt <rostedt@...dmis.org>
To:     Qi Hou <qi.hou@...driver.com>
Cc:     <mingo@...hat.com>, <tglx@...utronix.de>,
        <linux-kernel@...r.kernel.org>, <C.Emde@...dl.org>,
        <paul.gortmaker@...driver.com>, <bruce.ashfield@...driver.com>
Subject: Re: [PATCH] lockdep: call time_hardirqs_off after clearing
 hardirqs_enabled

On Tue, 14 Mar 2017 10:00:07 +0800
Qi Hou <qi.hou@...driver.com> wrote:

> diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
> index 577f026..e8b35e4 100644
> --- a/kernel/locking/lockdep.c
> +++ b/kernel/locking/lockdep.c
> @@ -2627,8 +2627,6 @@ __visible void trace_hardirqs_off_caller(unsigned long ip)
>  {
>  	struct task_struct *curr = current;
>  
> -	time_hardirqs_off(CALLER_ADDR0, ip);
> -
>  	if (unlikely(!debug_locks || current->lockdep_recursion))
>  		return;

You do realize that this breaks irqsoff tracing if lockdep ever
triggers. Right?

-- Steve

>  
> @@ -2649,6 +2647,8 @@ __visible void trace_hardirqs_off_caller(unsigned long ip)
>  		debug_atomic_inc(hardirqs_off_events);
>  	} else
>  		debug_atomic_inc(redundant_hardirqs_off);
> +
> +	time_hardirqs_off(CALLER_ADDR0, ip);
>  }
>  EXPORT_SYMBOL(trace_hardirqs_off_caller);
>