Re: [PATCH v7 6/8] mmc: sdhci-esdhc-imx: use pm_runtime_resume_and_get() in suspend

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:

Pre-existing issues:
- [High] Unchecked pm_runtime_get_sync() in sdhci_esdhc_imx_remove() leads to kernel panic on failure.
--

--- Patch [6]: [PATCH v7 6/8] mmc: sdhci-esdhc-imx: use pm_runtime_resume_and_get() in suspend ---
commit f0a062e3623dc14c66d429be48e9ae36028fd188
Author: Luke Wang <ziniu.wang_1@nxp.com>

mmc: sdhci-esdhc-imx: use pm_runtime_resume_and_get() in suspend

This patch replaces pm_runtime_get_sync() with pm_runtime_resume_and_get() in
sdhci_esdhc_suspend(). It properly returns an error if resuming fails,
preventing a kernel panic caused by accessing hardware registers when the
device is unclocked.

> diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c b/drivers/mmc/host/sdhci-esdhc-imx.c
> index 6e792bee25bfa..ec531a9451c4e 100644
> --- a/drivers/mmc/host/sdhci-esdhc-imx.c
> +++ b/drivers/mmc/host/sdhci-esdhc-imx.c
> @@ -2061,7 +2061,9 @@ static int sdhci_esdhc_suspend(struct device *dev)
>  	 * 2, make sure the pm_runtime_force_resume() in sdhci_esdhc_resume() really
>  	 *    invoke its ->runtime_resume callback (needs_force_resume = 1).
>  	 */
> -	pm_runtime_get_sync(dev);
> +	ret = pm_runtime_resume_and_get(dev);
> +	if (ret)
> +		return ret;

[Severity: High]
This is a pre-existing issue, but since the commit message notes that accessing
hardware registers while the device is unclocked causes a kernel panic, could
this same panic occur in sdhci_esdhc_imx_remove()?

Looking at the device removal path:

drivers/mmc/host/sdhci-esdhc-imx.c:sdhci_esdhc_imx_remove() {
	...
	pm_runtime_get_sync(&pdev->dev);
	dead = (readl(host->ioaddr + SDHCI_INT_STATUS) == 0xffffffff);
	...
}

If pm_runtime_get_sync() fails to resume the device here, execution proceeds to
readl() on the unclocked hardware. Should we also use
pm_runtime_resume_and_get() and check the return value in the remove path to
avoid a panic during unbind?

>  
>  	if ((imx_data->socdata->flags & ESDHC_FLAG_STATE_LOST_IN_LPMODE) &&
>  		(host->tuning_mode != SDHCI_TUNING_MODE_1)) {
>

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260715071818.272318-1-ziniu.wang_1@oss.nxp.com?part=6