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Message-ID: <0d286c66-2fb7-f91c-8d77-936a311b77de@kernel.org>
Date:   Tue, 26 Jul 2022 22:06:51 +0200
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Subject: Re: [PATCH V7 02/16] rv: Add runtime reactors interface
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To:     Steven Rostedt <rostedt@goodmis.org>
Cc:     Wim Van Sebroeck <wim@linux-watchdog.org>,
        Guenter Roeck <linux@roeck-us.net>,
        Jonathan Corbet <corbet@lwn.net>,
        Ingo Molnar <mingo@redhat.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Peter Zijlstra <peterz@infradead.org>,
        Will Deacon <will@kernel.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Marco Elver <elver@google.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        "Paul E. McKenney" <paulmck@kernel.org>,
        Shuah Khan <skhan@linuxfoundation.org>,
        Gabriele Paoloni <gpaoloni@redhat.com>,
        Juri Lelli <juri.lelli@redhat.com>,
        Clark Williams <williams@redhat.com>,
        Tao Zhou <tao.zhou@linux.dev>,
        Randy Dunlap <rdunlap@infradead.org>,
        linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-trace-devel@vger.kernel.org
References: <cover.1658778484.git.bristot@kernel.org>
 <516e8767f20f47b185b7dc0dceb1f1d3abb36dce.1658778484.git.bristot@kernel.org>
 <20220726122629.2a99cb6e@gandalf.local.home>
From:   Daniel Bristot de Oliveira <bristot@kernel.org>
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On 7/26/22 18:26, Steven Rostedt wrote:
> On Mon, 25 Jul 2022 22:11:14 +0200
> Daniel Bristot de Oliveira <bristot@kernel.org> wrote:
> 
>> +/**
>> + * reactor_cleanup_monitor - cleanup a monitor reference
>> + * @mdef:       monitor's definition.
>> + */
>> +void reactor_cleanup_monitor(struct rv_monitor_def *mdef)
>> +{
>> +	mdef->rdef->counter--;
>> +}
>> +
> 
> Doesn't this require a lock? Also you might want to add a WARN_ONCE() if it
> goes below zero.

reactor_populate_monitor() and reactor_cleanup_monitor() should be called with
lock taken... adding lockdep check.

oops, I was not actually calling it yet. Not a BUG, as we do not unload reactors,
it was BUG on the way to happen :-)

Adding a WARN_ONCE().

-- Daniel

> 
> -- Steve