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SubjectRe: [PATCH] mmc: host: fix a possible null pointer access.
On Tue, 17 Dec 2019 at 04:18, Pan Zhang <zhangpan26@huawei.com> wrote:
>
> 3419 if (host->slot &&
> 3420 (mmc_can_gpio_cd(host->slot->mmc) ||
> 3421 !mmc_card_is_removable(host->slot->mmc))) {
> 3422 ret = clk_prepare_enable(host->biu_clk);
> 3423 if (ret)
> 3424 return ret;
> 3425 }
>
> We previously assumed 'host->slot' could be null (see line 3419).
>
> The following situation is similar, so add a judgement.
>
> Signed-off-by: Pan Zhang <zhangpan26@huawei.com>
> ---
> drivers/mmc/host/dw_mmc.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
> index fc9d4d0..8e27c52 100644
> --- a/drivers/mmc/host/dw_mmc.c
> +++ b/drivers/mmc/host/dw_mmc.c
> @@ -3454,7 +3454,7 @@ int dw_mci_runtime_resume(struct device *dev)
> mci_writel(host, CTRL, SDMMC_CTRL_INT_ENABLE);
>
>
> - if (host->slot->mmc->pm_flags & MMC_PM_KEEP_POWER)
> + if (host->slot && (host->slot->mmc->pm_flags & MMC_PM_KEEP_POWER))
> dw_mci_set_ios(host->slot->mmc, &host->slot->mmc->ios);

This shouldn't be a problem as the ->runtime_resume() callback can't
be invoked, unless there is a slot.

>
> /* Force setup bus to guarantee available clock output */
> --
> 2.7.4
>

Kind regards
Uffe

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