From:   <miles.chen@mediatek.com>
To:     <zhou1615@umn.edu>
CC:     <kjlu@umn.edu>, <linux-arm-kernel@lists.infradead.org>,
        <linux-clk@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <linux-mediatek@lists.infradead.org>, <matthias.bgg@gmail.com>,
        <miles.chen@mediatek.com>, <mturquette@baylibre.com>,
        <sboyd@kernel.org>, <wendell.lin@mediatek.com>
Subject: Re: [PATCH] clk: mediatek: mt6779: Fix a NULL pointer dereference in clk_mt6779_top_probe()
Date:   Wed, 1 Dec 2021 17:33:21 +0800
Message-ID: <20211201093321.31312-1-miles.chen@mediatek.com>
In-Reply-To: <20211130173634.212143-1-zhou1615@umn.edu>
References: <20211130173634.212143-1-zhou1615@umn.edu>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

Hi Qingyang,

> Fix this bug by adding a check of clk_data.
> 
> Another way to fix this bug is to add a check of clk_data in
> mtk_clk_register_muxes(), which may solve many similar bugs but could
> cause potential problems to previously correct cases as the API is changed.
> 
> This bug was found by a static analyzer. The analysis employs
> differential checking to identify inconsistent security operations
> (e.g., checks or kfrees) between two code paths and confirms that the
> inconsistent operations are not recovered in the current function or
> the callers, so they constitute bugs.
> 
> Note that, as a bug found by static analysis, it can be a false
> positive or hard to trigger. Multiple researchers have cross-reviewed
> the bug.
> 
> Builds with CONFIG_COMMON_CLK_MT6779=y show no new warnings,
> and our static analyzer no longer warns about this code.
> 
> Fixes: 710774e04861 ("clk: mediatek: Add MT6779 clock support")
> Signed-off-by: Zhou Qingyang <zhou1615@umn.edu>
>

thanks,
Reviewed-by: Miles Chen <miles.chen@mediatek.com>