Re: [PATCH] dw_mmc: fix multiple drv_data NULL dereferences

[James Hogan <james.hogan@imgtec.com>]

On 17/10/12 10:11, Will Newton wrote:
> Looks good to me too.
> 
> Acked-by: Will Newton <will.newton@imgtec.com>
> 
> On Wed, Oct 17, 2012 at 3:06 AM, Jaehoon Chung <jh80.chung@samsung.com> wrote:
>> Looks good to me.
>>
>> Acked-by: Jaehoon Chung <jh80.chung@samsung.com>

Thanks for the acks Thomas, Seungwon, Jaehoon and Will.

Chris: Any chance of queueing this patch for v3.7?

Thanks
James

>>
>> On 10/16/2012 05:43 PM, James Hogan wrote:
>>> Commit 800d78bfccb3d38116abfda2a5b9c8afdbd5ea21 ("mmc: dw_mmc: add
>>> support for implementation specific callbacks") merged in v3.7-rc1.
>>>
>>> The above commit introduced multiple NULL pointer dereferences when
>>> the default dw_mci_pltfm_probe() is used, as it sets host->drv_data to
>>> NULL, and that's only checked against NULL in 1 out of the 7 cases where
>>> it is dereferenced.
>>>
>>> Signed-off-by: James Hogan <james.hogan@imgtec.com>
>>> ---
>>>  drivers/mmc/host/dw_mmc-pltfm.c |    4 ++--
>>>  drivers/mmc/host/dw_mmc.c       |   29 +++++++++++++++++------------
>>>  2 files changed, 19 insertions(+), 14 deletions(-)
>>>
>>> diff --git a/drivers/mmc/host/dw_mmc-pltfm.c b/drivers/mmc/host/dw_mmc-pltfm.c
>>> index c960ca7..e595721 100644
>>> --- a/drivers/mmc/host/dw_mmc-pltfm.c
>>> +++ b/drivers/mmc/host/dw_mmc-pltfm.c
>>> @@ -50,8 +50,8 @@ int dw_mci_pltfm_register(struct platform_device *pdev,
>>>       if (!host->regs)
>>>               return -ENOMEM;
>>>
>>> -     if (host->drv_data->init) {
>>> -             ret = host->drv_data->init(host);
>>> +     if (drv_data && drv_data->init) {
>>> +             ret = drv_data->init(host);
>>>               if (ret)
>>>                       return ret;
>>>       }
>>> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
>>> index c2828f3..0dc6e33 100644
>>> --- a/drivers/mmc/host/dw_mmc.c
>>> +++ b/drivers/mmc/host/dw_mmc.c
>>> @@ -232,6 +232,7 @@ static u32 dw_mci_prepare_command(struct mmc_host *mmc, struct mmc_command *cmd)
>>>  {
>>>       struct mmc_data *data;
>>>       struct dw_mci_slot *slot = mmc_priv(mmc);
>>> +     struct dw_mci_drv_data *drv_data = slot->host->drv_data;
>>>       u32 cmdr;
>>>       cmd->error = -EINPROGRESS;
>>>
>>> @@ -261,8 +262,8 @@ static u32 dw_mci_prepare_command(struct mmc_host *mmc, struct mmc_command *cmd)
>>>                       cmdr |= SDMMC_CMD_DAT_WR;
>>>       }
>>>
>>> -     if (slot->host->drv_data->prepare_command)
>>> -             slot->host->drv_data->prepare_command(slot->host, &cmdr);
>>> +     if (drv_data && drv_data->prepare_command)
>>> +             drv_data->prepare_command(slot->host, &cmdr);
>>>
>>>       return cmdr;
>>>  }
>>> @@ -772,6 +773,7 @@ static void dw_mci_request(struct mmc_host *mmc, struct mmc_request *mrq)
>>>  static void dw_mci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
>>>  {
>>>       struct dw_mci_slot *slot = mmc_priv(mmc);
>>> +     struct dw_mci_drv_data *drv_data = slot->host->drv_data;
>>>       u32 regs;
>>>
>>>       /* set default 1 bit mode */
>>> @@ -807,8 +809,8 @@ static void dw_mci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
>>>               slot->clock = ios->clock;
>>>       }
>>>
>>> -     if (slot->host->drv_data->set_ios)
>>> -             slot->host->drv_data->set_ios(slot->host, ios);
>>> +     if (drv_data && drv_data->set_ios)
>>> +             drv_data->set_ios(slot->host, ios);
>>>
>>>       switch (ios->power_mode) {
>>>       case MMC_POWER_UP:
>>> @@ -1815,6 +1817,7 @@ static int dw_mci_init_slot(struct dw_mci *host, unsigned int id)
>>>  {
>>>       struct mmc_host *mmc;
>>>       struct dw_mci_slot *slot;
>>> +     struct dw_mci_drv_data *drv_data = host->drv_data;
>>>       int ctrl_id, ret;
>>>       u8 bus_width;
>>>
>>> @@ -1854,8 +1857,8 @@ static int dw_mci_init_slot(struct dw_mci *host, unsigned int id)
>>>       } else {
>>>               ctrl_id = to_platform_device(host->dev)->id;
>>>       }
>>> -     if (host->drv_data && host->drv_data->caps)
>>> -             mmc->caps |= host->drv_data->caps[ctrl_id];
>>> +     if (drv_data && drv_data->caps)
>>> +             mmc->caps |= drv_data->caps[ctrl_id];
>>>
>>>       if (host->pdata->caps2)
>>>               mmc->caps2 = host->pdata->caps2;
>>> @@ -1867,10 +1870,10 @@ static int dw_mci_init_slot(struct dw_mci *host, unsigned int id)
>>>       else
>>>               bus_width = 1;
>>>
>>> -     if (host->drv_data->setup_bus) {
>>> +     if (drv_data && drv_data->setup_bus) {
>>>               struct device_node *slot_np;
>>>               slot_np = dw_mci_of_find_slot_node(host->dev, slot->id);
>>> -             ret = host->drv_data->setup_bus(host, slot_np, bus_width);
>>> +             ret = drv_data->setup_bus(host, slot_np, bus_width);
>>>               if (ret)
>>>                       goto err_setup_bus;
>>>       }
>>> @@ -2035,6 +2038,7 @@ static struct dw_mci_board *dw_mci_parse_dt(struct dw_mci *host)
>>>       struct dw_mci_board *pdata;
>>>       struct device *dev = host->dev;
>>>       struct device_node *np = dev->of_node;
>>> +     struct dw_mci_drv_data *drv_data = host->drv_data;
>>>       int idx, ret;
>>>
>>>       pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
>>> @@ -2062,8 +2066,8 @@ static struct dw_mci_board *dw_mci_parse_dt(struct dw_mci *host)
>>>
>>>       of_property_read_u32(np, "card-detect-delay", &pdata->detect_delay_ms);
>>>
>>> -     if (host->drv_data->parse_dt) {
>>> -             ret = host->drv_data->parse_dt(host);
>>> +     if (drv_data && drv_data->parse_dt) {
>>> +             ret = drv_data->parse_dt(host);
>>>               if (ret)
>>>                       return ERR_PTR(ret);
>>>       }
>>> @@ -2080,6 +2084,7 @@ static struct dw_mci_board *dw_mci_parse_dt(struct dw_mci *host)
>>>
>>>  int dw_mci_probe(struct dw_mci *host)
>>>  {
>>> +     struct dw_mci_drv_data *drv_data = host->drv_data;
>>>       int width, i, ret = 0;
>>>       u32 fifo_size;
>>>       int init_slots = 0;
>>> @@ -2127,8 +2132,8 @@ int dw_mci_probe(struct dw_mci *host)
>>>       else
>>>               host->bus_hz = clk_get_rate(host->ciu_clk);
>>>
>>> -     if (host->drv_data->setup_clock) {
>>> -             ret = host->drv_data->setup_clock(host);
>>> +     if (drv_data && drv_data->setup_clock) {
>>> +             ret = drv_data->setup_clock(host);
>>>               if (ret) {
>>>                       dev_err(host->dev,
>>>                               "implementation specific clock setup failed\n");
>>>
>>
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