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Date:   Wed, 20 Jul 2022 11:21:02 -0400
From:   Steven Rostedt <rostedt@goodmis.org>
To:     Daniel Bristot de Oliveira <bristot@kernel.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>,
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        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>,
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        Randy Dunlap <rdunlap@infradead.org>,
        linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-trace-devel@vger.kernel.org
Subject: Re: [PATCH V6 01/16] rv: Add Runtime Verification (RV) interface
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        <69bb4c369b4f6f12014eb9ca3c28b74e4378c007.1658244826.git.bristot@kernel.org>
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On Tue, 19 Jul 2022 19:27:06 +0200
Daniel Bristot de Oliveira <bristot@kernel.org> wrote:

> +/*
> + * enabled_monitors interface.
> + */


Doesn't the rv_monitors_list need to be protected by the rv_interface_lock
mutex?

> +static void disable_all_monitors(void)
> +{
> +	struct rv_monitor_def *mdef;
> +

I think you need:

	mutex_lock(&rv_interface_lock);

> +	list_for_each_entry(mdef, &rv_monitors_list, list)
> +		disable_monitor(mdef);

	mutex_unlock(&rv_interface_lock);

> +}
> +
> +static int enabled_monitors_open(struct inode *inode, struct file *file)
> +{

As this gets called directly from the open system call.

> +	if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC))
> +		disable_all_monitors();
> +
> +	return seq_open(file, &enabled_monitors_seq_ops);
> +};
> +

[..]

> +
> +static const struct file_operations enabled_monitors_ops = {
> +	.open		= enabled_monitors_open,

Here.

-- Steve

> +	.read		= seq_read,
> +	.write		= enabled_monitors_write,
> +	.llseek		= seq_lseek,
> +	.release	= seq_release,
> +};