linux-kernel - Re: [PATCH V6 02/16] rv: Add runtime reactors interface

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <ba11409a-df46-8fad-61a9-256277c588c0@kernel.org>
Date:   Wed, 20 Jul 2022 18:50:39 +0200
From:   Daniel Bristot de Oliveira <bristot@...nel.org>
To:     Steven Rostedt <rostedt@...dmis.org>
Cc:     Wim Van Sebroeck <wim@...ux-watchdog.org>,
        Guenter Roeck <linux@...ck-us.net>,
        Jonathan Corbet <corbet@....net>,
        Ingo Molnar <mingo@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Peter Zijlstra <peterz@...radead.org>,
        Will Deacon <will@...nel.org>,
        Catalin Marinas <catalin.marinas@....com>,
        Marco Elver <elver@...gle.com>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        "Paul E. McKenney" <paulmck@...nel.org>,
        Shuah Khan <skhan@...uxfoundation.org>,
        Gabriele Paoloni <gpaoloni@...hat.com>,
        Juri Lelli <juri.lelli@...hat.com>,
        Clark Williams <williams@...hat.com>,
        Tao Zhou <tao.zhou@...ux.dev>,
        Randy Dunlap <rdunlap@...radead.org>,
        linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-trace-devel@...r.kernel.org
Subject: Re: [PATCH V6 02/16] rv: Add runtime reactors interface

On 7/20/22 18:41, Steven Rostedt wrote:
> On Tue, 19 Jul 2022 19:27:07 +0200
> Daniel Bristot de Oliveira <bristot@...nel.org> wrote:
> 
>> +/*
>> + * reacting_on interface.
>> + */
>> +static ssize_t reacting_on_read_data(struct file *filp,
>> +				     char __user *user_buf,
>> +				     size_t count, loff_t *ppos)
>> +{
>> +	char *buff;
>> +
>> +	mutex_lock(&rv_interface_lock);
>> +	buff = reacting_on ? "1\n" : "0\n";
>> +	mutex_unlock(&rv_interface_lock);
> Again, no need for the locks, but perhaps just to keep things sane:
> 
> 	buf = READ_ONCE(reacting_on) ? "1\n" : "0\n";

So, for all files that only read/write a single variable, use READ_ONCE/WRITE_ONCE without
locks? (and in all usage of that variable too).

-- Daniel
> -- Steve
>