linux-kernel - Re: *** SPAM *** [PATCH] i2c: mux: demux-pinctrl: do not deactivate a master that is not active

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Date:   Wed, 2 Mar 2022 20:42:08 +0100
From:   Marion & Christophe JAILLET <christophe.jaillet@...adoo.fr>
To:     Peter Rosin <peda@...ntia.se>,
        "linux-i2c@...r.kernel.org" <linux-i2c@...r.kernel.org>
Cc:     Wolfram Sang <wsa+renesas@...g-engineering.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: *** SPAM *** [PATCH] i2c: mux: demux-pinctrl: do not deactivate a
 master that is not active


Le 02/03/2022 à 12:22, Peter Rosin a écrit :
> Attempting to rollback the activation of the current master when
> the current master has not been activated is bad. priv->cur_chan
> and priv->cur_adap are both still zeroed out and the rollback
> may result in attempts to revert an of changeset that has not been
> applied and do result in calls to both del and put the zeroed out
> i2c_adapter. Maybe it crashes, or whatever, but it's bad in any
> case.
>
> Fixes: e9d1a0a41d44 ("i2c: mux: demux-pinctrl: Fix an error handling path in 'i2c_demux_pinctrl_probe()'")
> Cc: Christophe JAILLET <christophe.jaillet@...adoo.fr>
> Signed-off-by: Peter Rosin <peda@...ntia.se>
> ---
>   drivers/i2c/muxes/i2c-demux-pinctrl.c | 5 +++--
>   1 file changed, 3 insertions(+), 2 deletions(-)
>
> Hi!
>
> Either that, or I'm missing something. I found this issue when
> reading code, and have made no tests to verify if my analysis
> is correct.
>
> Cheers,
> Peter
>
> diff --git a/drivers/i2c/muxes/i2c-demux-pinctrl.c b/drivers/i2c/muxes/i2c-demux-pinctrl.c
> index 5365199a31f4..f7a7405d4350 100644
> --- a/drivers/i2c/muxes/i2c-demux-pinctrl.c
> +++ b/drivers/i2c/muxes/i2c-demux-pinctrl.c
> @@ -261,7 +261,7 @@ static int i2c_demux_pinctrl_probe(struct platform_device *pdev)
>   
>   	err = device_create_file(&pdev->dev, &dev_attr_available_masters);
>   	if (err)
> -		goto err_rollback;
> +		goto err_rollback_activation;
>   
>   	err = device_create_file(&pdev->dev, &dev_attr_current_master);
>   	if (err)
> @@ -271,8 +271,9 @@ static int i2c_demux_pinctrl_probe(struct platform_device *pdev)
>   
>   err_rollback_available:
>   	device_remove_file(&pdev->dev, &dev_attr_available_masters);
> -err_rollback:
> +err_rollback_activation:
>   	i2c_demux_deactivate_master(priv);
> +err_rollback:
>   	for (j = 0; j < i; j++) {
>   		of_node_put(priv->chan[j].parent_np);
>   		of_changeset_destroy(&priv->chan[j].chgset);

For what it worth, LGTM.

CJ