Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Tue, 11 Apr 2023 22:32:06 -0400
From:   Steven Rostedt <rostedt@goodmis.org>
To:     "Tze-nan Wu (=?UTF-8?B?5ZCz5r6k5Y2X?=)" <Tze-nan.Wu@mediatek.com>
Cc:     "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-trace-kernel@vger.kernel.org" 
        <linux-trace-kernel@vger.kernel.org>,
        "linux-mediatek@lists.infradead.org" 
        <linux-mediatek@lists.infradead.org>,
        "Cheng-Jui Wang (=?UTF-8?B?546L5q2j552/?=)" 
        <Cheng-Jui.Wang@mediatek.com>,
        "paulmck@kernel.org" <paulmck@kernel.org>,
        wsd_upstream <wsd_upstream@mediatek.com>,
        "Bobule Chang (=?UTF-8?B?5by15byY576p?=)" <bobule.chang@mediatek.com>,
        "stable@vger.kernel.org" <stable@vger.kernel.org>,
        "linux-arm-kernel@lists.infradead.org" 
        <linux-arm-kernel@lists.infradead.org>,
        "mhiramat@kernel.org" <mhiramat@kernel.org>,
        "angelogioacchino.delregno@collabora.com" 
        <angelogioacchino.delregno@collabora.com>,
        "npiggin@gmail.com" <npiggin@gmail.com>
Subject: Re: [PATCH v3] ring-buffer: Prevent inconsistent operation on
 cpu_buffer->resize_disabled
Message-ID: <20230411223206.0bc5794e@gandalf.local.home>
In-Reply-To: <ef0ebc2f0f934ff5c35719f1960d24a5838ff770.camel@mediatek.com>
References: <20230409024616.31099-1-Tze-nan.Wu@mediatek.com>
        <20230410073512.13362-1-Tze-nan.Wu@mediatek.com>
        <20230411124403.2a31e12d@gandalf.local.home>
        <ef0ebc2f0f934ff5c35719f1960d24a5838ff770.camel@mediatek.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8BIT
Precedence: bulk

On Wed, 12 Apr 2023 02:27:53 +0000
Tze-nan Wu (吳澤南) <Tze-nan.Wu@mediatek.com> wrote:

> > > @@ -5368,7 +5372,7 @@ void ring_buffer_reset_online_cpus(struct
> > > trace_buffer *buffer)
> > >       /* Make sure all commits have finished */
> > >       synchronize_rcu();
> > > 
> > > -     for_each_online_buffer_cpu(buffer, cpu) {
> > > +     for_each_cpu_and(cpu, buffer->cpumask, &reset_online_cpumask)  
> 
> Maybe we should use for_each_buffer_cpu(buffer, cpu) here?
> since a CPU may also came offline during synchronize_rcu().

Yeah, I guess that works too (not looking at the code at the moment though).

-- Steve

> 
> > > {
> > >               cpu_buffer = buffer->buffers[cpu];  
> >