* Re: [PATCH] mmc: host: dereference null return value
2020-06-23 4:06 ` [PATCH] mmc: host: dereference null return value haibo.chen
@ 2020-07-01 10:33 ` Adrian Hunter
2020-07-01 10:57 ` Marek Szyprowski
1 sibling, 0 replies; 3+ messages in thread
From: Adrian Hunter @ 2020-07-01 10:33 UTC (permalink / raw)
To: haibo.chen, ulf.hansson, linux-mmc, jh80.chung, kgene, krzk,
michal.simek, linux-samsung-soc
Cc: linux-imx
On 23/06/20 7:06 am, haibo.chen@nxp.com wrote:
> From: Haibo Chen <haibo.chen@nxp.com>
>
> of_match_node() has the opportunity to return NULL, so need to
> dereference null return value.
> This is reported by Coverity.
>
> Signed-off-by: Haibo Chen <haibo.chen@nxp.com>
> ---
> drivers/mmc/host/dw_mmc-exynos.c | 5 +++--
> drivers/mmc/host/dw_mmc-k3.c | 5 +++--
> drivers/mmc/host/dw_mmc-pltfm.c | 3 ++-
> drivers/mmc/host/sdhci-of-arasan.c | 2 ++
> 4 files changed, 10 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/mmc/host/dw_mmc-exynos.c b/drivers/mmc/host/dw_mmc-exynos.c
> index 5e3d95b63676..27ab55abb03f 100644
> --- a/drivers/mmc/host/dw_mmc-exynos.c
> +++ b/drivers/mmc/host/dw_mmc-exynos.c
> @@ -545,12 +545,13 @@ MODULE_DEVICE_TABLE(of, dw_mci_exynos_match);
>
> static int dw_mci_exynos_probe(struct platform_device *pdev)
> {
> - const struct dw_mci_drv_data *drv_data;
> + const struct dw_mci_drv_data *drv_data = NULL;
> const struct of_device_id *match;
> int ret;
>
> match = of_match_node(dw_mci_exynos_match, pdev->dev.of_node);
> - drv_data = match->data;
> + if (match)
> + drv_data = match->data;
Could be 1 line change:
drv_data = match ? match->data : NULL;
>
> pm_runtime_get_noresume(&pdev->dev);
> pm_runtime_set_active(&pdev->dev);
> diff --git a/drivers/mmc/host/dw_mmc-k3.c b/drivers/mmc/host/dw_mmc-k3.c
> index 50977ff18074..e8a148c306b3 100644
> --- a/drivers/mmc/host/dw_mmc-k3.c
> +++ b/drivers/mmc/host/dw_mmc-k3.c
> @@ -451,11 +451,12 @@ MODULE_DEVICE_TABLE(of, dw_mci_k3_match);
>
> static int dw_mci_k3_probe(struct platform_device *pdev)
> {
> - const struct dw_mci_drv_data *drv_data;
> + const struct dw_mci_drv_data *drv_data = NULL;
> const struct of_device_id *match;
>
> match = of_match_node(dw_mci_k3_match, pdev->dev.of_node);
> - drv_data = match->data;
> + if (match)
> + drv_data = match->data;
Could be 1 line change:
drv_data = match ? match->data : NULL;
>
> return dw_mci_pltfm_register(pdev, drv_data);
> }
> diff --git a/drivers/mmc/host/dw_mmc-pltfm.c b/drivers/mmc/host/dw_mmc-pltfm.c
> index 7de37f524a96..d3dcb96efd13 100644
> --- a/drivers/mmc/host/dw_mmc-pltfm.c
> +++ b/drivers/mmc/host/dw_mmc-pltfm.c
> @@ -78,7 +78,8 @@ static int dw_mci_pltfm_probe(struct platform_device *pdev)
>
> if (pdev->dev.of_node) {
> match = of_match_node(dw_mci_pltfm_match, pdev->dev.of_node);
> - drv_data = match->data;
> + if (match)
> + drv_data = match->data;
> }
>
> return dw_mci_pltfm_register(pdev, drv_data);
> diff --git a/drivers/mmc/host/sdhci-of-arasan.c b/drivers/mmc/host/sdhci-of-arasan.c
> index fb26e743e1fd..f2090f944a0e 100644
> --- a/drivers/mmc/host/sdhci-of-arasan.c
> +++ b/drivers/mmc/host/sdhci-of-arasan.c
> @@ -1520,6 +1520,8 @@ static int sdhci_arasan_probe(struct platform_device *pdev)
> const struct sdhci_arasan_of_data *data;
>
> match = of_match_node(sdhci_arasan_of_match, pdev->dev.of_node);
> + if (match == NULL)
(!match) seems to be preferred over (match == NULL)
> + return -ENOPARAM;
ENOPARAM is unconventional here. ENODEV or EINVAL are better
> data = match->data;
> host = sdhci_pltfm_init(pdev, data->pdata, sizeof(*sdhci_arasan));
>
>
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] mmc: host: dereference null return value
2020-06-23 4:06 ` [PATCH] mmc: host: dereference null return value haibo.chen
2020-07-01 10:33 ` Adrian Hunter
@ 2020-07-01 10:57 ` Marek Szyprowski
1 sibling, 0 replies; 3+ messages in thread
From: Marek Szyprowski @ 2020-07-01 10:57 UTC (permalink / raw)
To: haibo.chen, adrian.hunter, ulf.hansson, linux-mmc, jh80.chung,
kgene, krzk, michal.simek, linux-samsung-soc
Cc: linux-imx
Hi,
On 23.06.2020 06:06, haibo.chen@nxp.com wrote:
> From: Haibo Chen <haibo.chen@nxp.com>
>
> of_match_node() has the opportunity to return NULL, so need to
> dereference null return value.
> This is reported by Coverity.
>
> Signed-off-by: Haibo Chen <haibo.chen@nxp.com>
There is no point in such check for a NULL. The driver won't be
instantiated/probed if there is no matching node found first by the
upper level framework. If you really want to make this code cleaner,
please change it to use of_device_get_match_data().
> ---
> drivers/mmc/host/dw_mmc-exynos.c | 5 +++--
> drivers/mmc/host/dw_mmc-k3.c | 5 +++--
> drivers/mmc/host/dw_mmc-pltfm.c | 3 ++-
> drivers/mmc/host/sdhci-of-arasan.c | 2 ++
> 4 files changed, 10 insertions(+), 5 deletions(-)
> ...
Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland
^ permalink raw reply [flat|nested] 3+ messages in thread