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

From: Will Newton
Date: Wed Oct 17 2012 - 05:11:33 EST

Looks good to me too.

Acked-by: Will Newton <will.newton@xxxxxxxxxx>

On Wed, Oct 17, 2012 at 3:06 AM, Jaehoon Chung <jh80.chung@xxxxxxxxxxx> wrote:
> Looks good to me.
>
> Acked-by: Jaehoon Chung <jh80.chung@xxxxxxxxxxx>
>
> 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@xxxxxxxxxx>
>> ---
>> 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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