From: Robin Murphy <robin.murphy@arm.com> To: Aditya Pakki <pakki001@umn.edu> Cc: Ulf Hansson <ulf.hansson@linaro.org>, linux-samsung-soc@vger.kernel.org, Heiko Stuebner <heiko@sntech.de>, linux-mmc@vger.kernel.org, kjlu@umn.edu, linux-kernel@vger.kernel.org, Krzysztof Kozlowski <krzk@kernel.org>, Jaehoon Chung <jh80.chung@samsung.com>, linux-rockchip@lists.infradead.org, Kukjin Kim <kgene@kernel.org>, Jun Nie <jun.nie@linaro.org>, Shawn Guo <shawnguo@kernel.org>, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v2] mmc: dw_mmc: Fix to avoid potential NULL pointer dereference Date: Tue, 19 Mar 2019 11:09:48 +0000 [thread overview] Message-ID: <f3363524-f764-6652-9b16-3a8b0d30e6df@arm.com> (raw) In-Reply-To: <20190319014551.16559-1-pakki001@umn.edu> On 19/03/2019 01:45, Aditya Pakki wrote: > of_match_node can fail and return NULL in case no matching structure. > The patches checks for such a scenario and returns -ENXIO. FWIW, it looks like most of these instances could be cleaned up even more with of_device_get_match_data(). In general, do bear in mind that adding these NULL checks *everywhere* will in many cases just amount to useless dead code - a pure DT-based driver can usually freely assume of_match_node() returns non-NULL for its own device and match table in its probe routine, because that probe routine only ever gets called if of_driver_match_device() has already made the same match in the first place. Robin. > --- > V1: Added files dw_mmc-zx.c and dw_mmc-rockchip.c > > Signed-off-by: Aditya Pakki <pakki001@umn.edu> > --- > drivers/mmc/host/dw_mmc-exynos.c | 2 ++ > drivers/mmc/host/dw_mmc-k3.c | 2 ++ > drivers/mmc/host/dw_mmc-pltfm.c | 2 ++ > drivers/mmc/host/dw_mmc-rockchip.c | 2 ++ > drivers/mmc/host/dw_mmc-zx.c | 2 ++ > 5 files changed, 10 insertions(+) > > diff --git a/drivers/mmc/host/dw_mmc-exynos.c b/drivers/mmc/host/dw_mmc-exynos.c > index d46c3439b508..8a75d7314606 100644 > --- a/drivers/mmc/host/dw_mmc-exynos.c > +++ b/drivers/mmc/host/dw_mmc-exynos.c > @@ -554,6 +554,8 @@ static int dw_mci_exynos_probe(struct platform_device *pdev) > int ret; > > match = of_match_node(dw_mci_exynos_match, pdev->dev.of_node); > + if (!match) > + return -ENXIO; > drv_data = match->data; > > pm_runtime_get_noresume(&pdev->dev); > diff --git a/drivers/mmc/host/dw_mmc-k3.c b/drivers/mmc/host/dw_mmc-k3.c > index 89cdb3d533bb..cc50b7546a20 100644 > --- a/drivers/mmc/host/dw_mmc-k3.c > +++ b/drivers/mmc/host/dw_mmc-k3.c > @@ -459,6 +459,8 @@ static int dw_mci_k3_probe(struct platform_device *pdev) > const struct of_device_id *match; > > match = of_match_node(dw_mci_k3_match, pdev->dev.of_node); > + if (!match) > + return -ENXIO; > drv_data = match->data; > > 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 58c13e21bd5a..b1948989f617 100644 > --- a/drivers/mmc/host/dw_mmc-pltfm.c > +++ b/drivers/mmc/host/dw_mmc-pltfm.c > @@ -82,6 +82,8 @@ 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); > + if (!match) > + return -ENXIO; > drv_data = match->data; > } > > diff --git a/drivers/mmc/host/dw_mmc-rockchip.c b/drivers/mmc/host/dw_mmc-rockchip.c > index 8c86a800a8fd..20e3471260ea 100644 > --- a/drivers/mmc/host/dw_mmc-rockchip.c > +++ b/drivers/mmc/host/dw_mmc-rockchip.c > @@ -344,6 +344,8 @@ static int dw_mci_rockchip_probe(struct platform_device *pdev) > return -ENODEV; > > match = of_match_node(dw_mci_rockchip_match, pdev->dev.of_node); > + if (!match) > + return -ENXIO; > drv_data = match->data; > > pm_runtime_get_noresume(&pdev->dev); > diff --git a/drivers/mmc/host/dw_mmc-zx.c b/drivers/mmc/host/dw_mmc-zx.c > index c06b5393312f..abea35431045 100644 > --- a/drivers/mmc/host/dw_mmc-zx.c > +++ b/drivers/mmc/host/dw_mmc-zx.c > @@ -213,6 +213,8 @@ static int dw_mci_zx_probe(struct platform_device *pdev) > const struct of_device_id *match; > > match = of_match_node(dw_mci_zx_match, pdev->dev.of_node); > + if (!match) > + return -ENXIO; > drv_data = match->data; > > return dw_mci_pltfm_register(pdev, drv_data); >
WARNING: multiple messages have this Message-ID (diff)
From: Robin Murphy <robin.murphy@arm.com> To: Aditya Pakki <pakki001@umn.edu> Cc: Ulf Hansson <ulf.hansson@linaro.org>, linux-samsung-soc@vger.kernel.org, Heiko Stuebner <heiko@sntech.de>, linux-mmc@vger.kernel.org, kjlu@umn.edu, linux-kernel@vger.kernel.org, Krzysztof Kozlowski <krzk@kernel.org>, Jaehoon Chung <jh80.chung@samsung.com>, linux-rockchip@lists.infradead.org, Kukjin Kim <kgene@kernel.org>, Jun Nie <jun.nie@linaro.org>, Shawn Guo <shawnguo@kernel.org>, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v2] mmc: dw_mmc: Fix to avoid potential NULL pointer dereference Date: Tue, 19 Mar 2019 11:09:48 +0000 [thread overview] Message-ID: <f3363524-f764-6652-9b16-3a8b0d30e6df@arm.com> (raw) In-Reply-To: <20190319014551.16559-1-pakki001@umn.edu> On 19/03/2019 01:45, Aditya Pakki wrote: > of_match_node can fail and return NULL in case no matching structure. > The patches checks for such a scenario and returns -ENXIO. FWIW, it looks like most of these instances could be cleaned up even more with of_device_get_match_data(). In general, do bear in mind that adding these NULL checks *everywhere* will in many cases just amount to useless dead code - a pure DT-based driver can usually freely assume of_match_node() returns non-NULL for its own device and match table in its probe routine, because that probe routine only ever gets called if of_driver_match_device() has already made the same match in the first place. Robin. > --- > V1: Added files dw_mmc-zx.c and dw_mmc-rockchip.c > > Signed-off-by: Aditya Pakki <pakki001@umn.edu> > --- > drivers/mmc/host/dw_mmc-exynos.c | 2 ++ > drivers/mmc/host/dw_mmc-k3.c | 2 ++ > drivers/mmc/host/dw_mmc-pltfm.c | 2 ++ > drivers/mmc/host/dw_mmc-rockchip.c | 2 ++ > drivers/mmc/host/dw_mmc-zx.c | 2 ++ > 5 files changed, 10 insertions(+) > > diff --git a/drivers/mmc/host/dw_mmc-exynos.c b/drivers/mmc/host/dw_mmc-exynos.c > index d46c3439b508..8a75d7314606 100644 > --- a/drivers/mmc/host/dw_mmc-exynos.c > +++ b/drivers/mmc/host/dw_mmc-exynos.c > @@ -554,6 +554,8 @@ static int dw_mci_exynos_probe(struct platform_device *pdev) > int ret; > > match = of_match_node(dw_mci_exynos_match, pdev->dev.of_node); > + if (!match) > + return -ENXIO; > drv_data = match->data; > > pm_runtime_get_noresume(&pdev->dev); > diff --git a/drivers/mmc/host/dw_mmc-k3.c b/drivers/mmc/host/dw_mmc-k3.c > index 89cdb3d533bb..cc50b7546a20 100644 > --- a/drivers/mmc/host/dw_mmc-k3.c > +++ b/drivers/mmc/host/dw_mmc-k3.c > @@ -459,6 +459,8 @@ static int dw_mci_k3_probe(struct platform_device *pdev) > const struct of_device_id *match; > > match = of_match_node(dw_mci_k3_match, pdev->dev.of_node); > + if (!match) > + return -ENXIO; > drv_data = match->data; > > 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 58c13e21bd5a..b1948989f617 100644 > --- a/drivers/mmc/host/dw_mmc-pltfm.c > +++ b/drivers/mmc/host/dw_mmc-pltfm.c > @@ -82,6 +82,8 @@ 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); > + if (!match) > + return -ENXIO; > drv_data = match->data; > } > > diff --git a/drivers/mmc/host/dw_mmc-rockchip.c b/drivers/mmc/host/dw_mmc-rockchip.c > index 8c86a800a8fd..20e3471260ea 100644 > --- a/drivers/mmc/host/dw_mmc-rockchip.c > +++ b/drivers/mmc/host/dw_mmc-rockchip.c > @@ -344,6 +344,8 @@ static int dw_mci_rockchip_probe(struct platform_device *pdev) > return -ENODEV; > > match = of_match_node(dw_mci_rockchip_match, pdev->dev.of_node); > + if (!match) > + return -ENXIO; > drv_data = match->data; > > pm_runtime_get_noresume(&pdev->dev); > diff --git a/drivers/mmc/host/dw_mmc-zx.c b/drivers/mmc/host/dw_mmc-zx.c > index c06b5393312f..abea35431045 100644 > --- a/drivers/mmc/host/dw_mmc-zx.c > +++ b/drivers/mmc/host/dw_mmc-zx.c > @@ -213,6 +213,8 @@ static int dw_mci_zx_probe(struct platform_device *pdev) > const struct of_device_id *match; > > match = of_match_node(dw_mci_zx_match, pdev->dev.of_node); > + if (!match) > + return -ENXIO; > drv_data = match->data; > > return dw_mci_pltfm_register(pdev, drv_data); > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2019-03-19 11:09 UTC|newest] Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-03-19 1:45 [PATCH v2] mmc: dw_mmc: Fix to avoid potential NULL pointer dereference Aditya Pakki 2019-03-19 1:45 ` Aditya Pakki 2019-03-19 11:09 ` Robin Murphy [this message] 2019-03-19 11:09 ` Robin Murphy
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