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Date:   Sun, 9 Apr 2023 19:30:53 +0700
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Subject: Re: [PATCH v2] ring-buffer: Prevent inconsistent operation on
 cpu_buffer->resize_disabled
To:     Tze-nan Wu <Tze-nan.Wu@mediatek.com>, rostedt@goodmis.org,
        mhiramat@kernel.org
Cc:     bobule.chang@mediatek.com, wsd_upstream@mediatek.com,
        stable@vger.kernel.org,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@collabora.com>,
        linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        linux-mediatek@lists.infradead.org
References: <20230408052226.25268-1-Tze-nan.Wu@mediatek.com>
 <20230409024616.31099-1-Tze-nan.Wu@mediatek.com>
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From:   Bagas Sanjaya <bagasdotme@gmail.com>
In-Reply-To: <20230409024616.31099-1-Tze-nan.Wu@mediatek.com>
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On 4/9/23 09:46, Tze-nan Wu wrote:
> This issue can be reproduced by "echo 0 > trace" and hotplug cpu at the
> same time. After reproducing success, we can find out buffer_size_kb
> will not be functional anymore.
> 

Do you mean disabling tracing while hotplugging CPU? Or disabling both
tracing and hotplug CPU?

> This patch uses cpus_read_lock() to prevent cpu_online_mask being changed
> between two different "for_each_online_buffer_cpu".
> 

"Use cpu_read_lock() to prevent ..."

> Changes in v2:
>   Use cpus_read_lock() instead of copying cpu_online_mask at the entry of
>   function
> 

To resolve kernel test robot warnings ([1] and [2])? Or have they been fixed?

[1]: https://lore.kernel.org/stable/202304081615.eiaqpbV8-lkp@intel.com/
[2]: https://lore.kernel.org/stable/202304082051.Dp50upfS-lkp@intel.com/

Thanks.

-- 
An old man doll... just what I always wanted! - Clara