On 19 October 2016 at 14:36, Maxime Ripard
<maxime.ripard@xxxxxxxxxxxxxxxxxx> wrote:
> VMMC is an optional regulator, which means that mmc_regulator_get_supply
> will only return an error in case of a deferred probe, but not when the
> regulator is not set in the DT.
>
> However, the sunxi driver assumes that VMMC is always there, and doesn't
> check the value of the regulator pointer before using it, which obviously
> leads to a (close to) null pointer dereference.
>
> Add proper checks to prevent that.
>
> Signed-off-by: Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx>
> ---
> drivers/mmc/host/sunxi-mmc.c | 18 +++++++++++++-----
> 1 file changed, 13 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/mmc/host/sunxi-mmc.c b/drivers/mmc/host/sunxi-mmc.c
> index c0a5c676d0e8..45a051e7d650 100644
> --- a/drivers/mmc/host/sunxi-mmc.c
> +++ b/drivers/mmc/host/sunxi-mmc.c
> @@ -822,10 +822,16 @@ static void sunxi_mmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
> break;
>
> case MMC_POWER_UP:
> - host->ferror = mmc_regulator_set_ocr(mmc, mmc->supply.vmmc,
> - ios->vdd);
> - if (host->ferror)
> - return;
> + if (!IS_ERR(mmc->supply.vmmc)) {
> + host->ferror = mmc_regulator_set_ocr(mmc,
> + mmc->supply.vmmc,
> + ios->vdd);
> + if (host->ferror) {
> + dev_err(mmc_dev(mmc),
> + "failed to enable vmmc\n");
The print here is already taken care of by mmc_regulator_set_ocr()
> + return;
> + }
> + }
>
> if (!IS_ERR(mmc->supply.vqmmc)) {
> host->ferror = regulator_enable(mmc->supply.vqmmc);
> @@ -847,7 +853,9 @@ static void sunxi_mmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
> case MMC_POWER_OFF:
> dev_dbg(mmc_dev(mmc), "power off!\n");
> sunxi_mmc_reset_host(host);
> - mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, 0);
> + if (!IS_ERR(mmc->supply.vmmc))
> + mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, 0);
> +
> if (!IS_ERR(mmc->supply.vqmmc) && host->vqmmc_enabled)
> regulator_disable(mmc->supply.vqmmc);
> host->vqmmc_enabled = false;
> --
> 2.9.3
>
Otherwise this looks good to me!
Kind regards
Uffe
--
To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
