[U-Boot] [PATCH] mmc: sdhci: fix NULL pointer access when host->ops is not set

[Masahiro Yamada]

Tom did not pull MMC updates issued just before v2017.01
and he was right.


2017-01-13 11:51 GMT+09:00 Masahiro Yamada <yamada.masahiro at socionext.com>:
> Until recently, sdhci_ops was used only for overriding IO accessors.
> (so, host->ops was not set by any drivers except bcm2835_sdhci.c)
>
> Now, we have more optional callbacks, get_cd, set_control_reg, and
> set_clock.  However, the code
>
>     if (host->ops->get_cd)
>             host->ops->get_cd(host);
>
> ... expects host->ops is set for all drivers.
>
> Commit 5e96217f0434 ("mmc: pic32_sdhci: move the code to
> pic32_sdhci.c") and commit 62226b68631b ("mmc: sdhci: move the
> callback function into sdhci_ops") added sdhci_ops for pic32_sdhci.c
> and s5p_sdhci.c, but the other drivers still do not (need not) set
> host->ops because all callbacks in sdhci_ops are optional.
>
> host->ops must be checked to avoid the system crash caused by NULL
> pointer access.
>
> Signed-off-by: Masahiro Yamada <yamada.masahiro at socionext.com>
> ---
>
>  drivers/mmc/sdhci.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/mmc/sdhci.c b/drivers/mmc/sdhci.c
> index 3a1f4f7..5b404ff 100644
> --- a/drivers/mmc/sdhci.c
> +++ b/drivers/mmc/sdhci.c
> @@ -359,7 +359,7 @@ static int sdhci_set_clock(struct mmc *mmc, unsigned int clock)
>                 div >>= 1;
>         }
>
> -       if (host->ops->set_clock)
> +       if (host->ops && host->ops->set_clock)
>                 host->ops->set_clock(host, div);
>
>         clk |= (div & SDHCI_DIV_MASK) << SDHCI_DIVIDER_SHIFT;
> @@ -427,7 +427,7 @@ static int sdhci_set_ios(struct mmc *mmc)
>         u32 ctrl;
>         struct sdhci_host *host = mmc->priv;
>
> -       if (host->ops->set_control_reg)
> +       if (host->ops && host->ops->set_control_reg)
>                 host->ops->set_control_reg(host);
>
>         if (mmc->clock != host->clock)
> @@ -480,7 +480,7 @@ static int sdhci_init(struct mmc *mmc)
>
>         sdhci_set_power(host, fls(mmc->cfg->voltages) - 1);
>
> -       if (host->ops->get_cd)
> +       if (host->ops && host->ops->get_cd)
>                 host->ops->get_cd(host);
>
>         /* Enable only interrupts served by the SD controller */
> --
> 2.7.4
>
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-- 
Best Regards
Masahiro Yamada