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Subject: Re: [PATCH] i2c: core: fix NULL pointer dereference in
 suspend/resume callbacks
To:     linux-pm@vger.kernel.org, linux-i2c@vger.kernel.org,
        linux-kernel@vger.kernel.org
Cc:     Wolfram Sang <wsa@the-dreams.de>,
        Bibby Hsieh <bibby.hsieh@mediatek.com>,
        Tomasz Figa <tfiga@chromium.org>,
        Bartosz Golaszewski <bgolaszewski@baylibre.com>,
        srv_heupstream@mediatek.com,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
        linux-samsung-soc@vger.kernel.org
From:   Marek Szyprowski <m.szyprowski@samsung.com>
Message-ID: <34736047-3fc8-385b-cdea-79b061deb7b4@samsung.com>
Date:   Fri, 22 May 2020 13:15:12 +0200
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Hi All,

On 22.05.2020 12:13, Marek Szyprowski wrote:
> Commit 6fe12cdbcfe3 ("i2c: core: support bus regulator controlling in
> adapter") added generic suspend and resume functions for i2c devices.
> Those functions unconditionally access an i2c_client structure assigned
> to the given i2c device. However, there exist i2c devices in the system
> without a valid i2c_client. Add the needed check before accessing the
> i2c_client.

Just one more comment. The devices without i2c_client structure are the 
i2c 'devices' associated with the respective i2c bus. They are visible 
in /sys:

ls -l /sys/bus/i2c/devices/i2c-*

I wonder if this patch has been ever tested with system suspend/resume, 
as those devices are always available in the system...

> ...

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland