[PATCH] soc/fsl/qe: fix err handling of ucc_of_parse_tdm

[PATCH] soc/fsl/qe: fix err handling of ucc_of_parse_tdm

[Yi Wang]

From: Wen Yang <wen.yang99@zte.com.cn>

Currently there are 2 problems with the ucc_of_parse_tdm function:
1,a possible null pointer dereference in ucc_of_parse_tdm,
detected by the semantic patch deref_null.cocci,
with the following warning:
drivers/soc/fsl/qe/qe_tdm.c:177:21-24: ERROR: pdev is NULL but dereferenced.
2,dev gets modified, so in any case that devm_iounmap() will fail even when
the new pdev is valid, because the iomap was done with a different pdev.
This patch fixes them.

Suggested-by: Christophe LEROY <christophe.leroy@c-s.fr>
Signed-off-by: Wen Yang <wen.yang99@zte.com.cn>
CC: Julia Lawall <julia.lawall@lip6.fr>
CC: Zhao Qiang <qiang.zhao@nxp.com>
---
 drivers/soc/fsl/qe/qe_tdm.c | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/drivers/soc/fsl/qe/qe_tdm.c b/drivers/soc/fsl/qe/qe_tdm.c
index f78c346..9a29f0b 100644
--- a/drivers/soc/fsl/qe/qe_tdm.c
+++ b/drivers/soc/fsl/qe/qe_tdm.c
@@ -47,7 +47,7 @@ int ucc_of_parse_tdm(struct device_node *np, struct ucc_tdm *utdm,
 	struct resource *res;
 	struct device_node *np2;
 	static int siram_init_flag;
-	struct platform_device *pdev;
+	struct platform_device *pdev_si, *pdev_siram;
 
 	sprop = of_get_property(np, "fsl,rx-sync-clock", NULL);
 	if (sprop) {
@@ -129,16 +129,16 @@ int ucc_of_parse_tdm(struct device_node *np, struct ucc_tdm *utdm,
 	if (!np2)
 		return -EINVAL;
 
-	pdev = of_find_device_by_node(np2);
-	if (!pdev) {
+	pdev_si = of_find_device_by_node(np2);
+	if (!pdev_si) {
 		pr_err("%pOFn: failed to lookup pdev\n", np2);
 		of_node_put(np2);
 		return -EINVAL;
 	}
 
 	of_node_put(np2);
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	utdm->si_regs = devm_ioremap_resource(&pdev->dev, res);
+	res = platform_get_resource(pdev_si, IORESOURCE_MEM, 0);
+	utdm->si_regs = devm_ioremap_resource(&pdev_si->dev, res);
 	if (IS_ERR(utdm->si_regs)) {
 		ret = PTR_ERR(utdm->si_regs);
 		goto err_miss_siram_property;
@@ -150,8 +150,8 @@ int ucc_of_parse_tdm(struct device_node *np, struct ucc_tdm *utdm,
 		goto err_miss_siram_property;
 	}
 
-	pdev = of_find_device_by_node(np2);
-	if (!pdev) {
+	pdev_siram = of_find_device_by_node(np2);
+	if (!pdev_siram) {
 		ret = -EINVAL;
 		pr_err("%pOFn: failed to lookup pdev\n", np2);
 		of_node_put(np2);
@@ -159,8 +159,8 @@ int ucc_of_parse_tdm(struct device_node *np, struct ucc_tdm *utdm,
 	}
 
 	of_node_put(np2);
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	utdm->siram = devm_ioremap_resource(&pdev->dev, res);
+	res = platform_get_resource(pdev_siram, IORESOURCE_MEM, 0);
+	utdm->siram = devm_ioremap_resource(&pdev_siram->dev, res);
 	if (IS_ERR(utdm->siram)) {
 		ret = PTR_ERR(utdm->siram);
 		goto err_miss_siram_property;
@@ -174,7 +174,7 @@ int ucc_of_parse_tdm(struct device_node *np, struct ucc_tdm *utdm,
 	return ret;
 
 err_miss_siram_property:
-	devm_iounmap(&pdev->dev, utdm->si_regs);
+	devm_iounmap(&pdev_si->dev, utdm->si_regs);
 	return ret;
 }
 EXPORT_SYMBOL(ucc_of_parse_tdm);
-- 
2.9.5

Re: [PATCH] soc/fsl/qe: fix err handling of ucc_of_parse_tdm

[Li Yang]

On Thu, Nov 22, 2018 at 2:42 PM Yi Wang <wang.yi59@zte.com.cn> wrote:
>
> From: Wen Yang <wen.yang99@zte.com.cn>
>
> Currently there are 2 problems with the ucc_of_parse_tdm function:
> 1,a possible null pointer dereference in ucc_of_parse_tdm,
> detected by the semantic patch deref_null.cocci,
> with the following warning:
> drivers/soc/fsl/qe/qe_tdm.c:177:21-24: ERROR: pdev is NULL but dereferenced.
> 2,dev gets modified, so in any case that devm_iounmap() will fail even when
> the new pdev is valid, because the iomap was done with a different pdev.
> This patch fixes them.

While we are at this, I think this logic need more serious fixing.  I
see there is no driver bind with the "fsl,t1040-qe-si" or
"fsl,t1040-qe-siram" device.  So allocating resources using devm_*()
with these devices won't provide a cleanup path for these resources
when the caller fails.  I think we should probably allocate resource
under device of caller (e.g. ucc-hdlc), so that when caller probe
fails or is removed it will trigger the cleanup.

>
> Suggested-by: Christophe LEROY <christophe.leroy@c-s.fr>
> Signed-off-by: Wen Yang <wen.yang99@zte.com.cn>
> CC: Julia Lawall <julia.lawall@lip6.fr>
> CC: Zhao Qiang <qiang.zhao@nxp.com>
> ---
>  drivers/soc/fsl/qe/qe_tdm.c | 20 ++++++++++----------
>  1 file changed, 10 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/soc/fsl/qe/qe_tdm.c b/drivers/soc/fsl/qe/qe_tdm.c
> index f78c346..9a29f0b 100644
> --- a/drivers/soc/fsl/qe/qe_tdm.c
> +++ b/drivers/soc/fsl/qe/qe_tdm.c
> @@ -47,7 +47,7 @@ int ucc_of_parse_tdm(struct device_node *np, struct ucc_tdm *utdm,
>         struct resource *res;
>         struct device_node *np2;
>         static int siram_init_flag;
> -       struct platform_device *pdev;
> +       struct platform_device *pdev_si, *pdev_siram;
>
>         sprop = of_get_property(np, "fsl,rx-sync-clock", NULL);
>         if (sprop) {
> @@ -129,16 +129,16 @@ int ucc_of_parse_tdm(struct device_node *np, struct ucc_tdm *utdm,
>         if (!np2)
>                 return -EINVAL;
>
> -       pdev = of_find_device_by_node(np2);
> -       if (!pdev) {
> +       pdev_si = of_find_device_by_node(np2);
> +       if (!pdev_si) {
>                 pr_err("%pOFn: failed to lookup pdev\n", np2);
>                 of_node_put(np2);
>                 return -EINVAL;
>         }
>
>         of_node_put(np2);
> -       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> -       utdm->si_regs = devm_ioremap_resource(&pdev->dev, res);
> +       res = platform_get_resource(pdev_si, IORESOURCE_MEM, 0);
> +       utdm->si_regs = devm_ioremap_resource(&pdev_si->dev, res);
>         if (IS_ERR(utdm->si_regs)) {
>                 ret = PTR_ERR(utdm->si_regs);
>                 goto err_miss_siram_property;
> @@ -150,8 +150,8 @@ int ucc_of_parse_tdm(struct device_node *np, struct ucc_tdm *utdm,
>                 goto err_miss_siram_property;
>         }
>
> -       pdev = of_find_device_by_node(np2);
> -       if (!pdev) {
> +       pdev_siram = of_find_device_by_node(np2);
> +       if (!pdev_siram) {
>                 ret = -EINVAL;
>                 pr_err("%pOFn: failed to lookup pdev\n", np2);
>                 of_node_put(np2);
> @@ -159,8 +159,8 @@ int ucc_of_parse_tdm(struct device_node *np, struct ucc_tdm *utdm,
>         }
>
>         of_node_put(np2);
> -       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> -       utdm->siram = devm_ioremap_resource(&pdev->dev, res);
> +       res = platform_get_resource(pdev_siram, IORESOURCE_MEM, 0);
> +       utdm->siram = devm_ioremap_resource(&pdev_siram->dev, res);
>         if (IS_ERR(utdm->siram)) {
>                 ret = PTR_ERR(utdm->siram);
>                 goto err_miss_siram_property;
> @@ -174,7 +174,7 @@ int ucc_of_parse_tdm(struct device_node *np, struct ucc_tdm *utdm,
>         return ret;
>
>  err_miss_siram_property:
> -       devm_iounmap(&pdev->dev, utdm->si_regs);
> +       devm_iounmap(&pdev_si->dev, utdm->si_regs);
>         return ret;
>  }
>  EXPORT_SYMBOL(ucc_of_parse_tdm);
> --
> 2.9.5
>

RE: [PATCH] soc/fsl/qe: fix err handling of ucc_of_parse_tdm

[Qiang Zhao]

Hi Wen,

Will you send another version to resolve the issue described in the comments?

BR
Qiang

> -----Original Message-----
> From: Li Yang <leoyang.li@nxp.com>
> Sent: 2018年12月6日 4:10
> To: wang.yi59@zte.com.cn
> Cc: Qiang Zhao <qiang.zhao@nxp.com>; zhong.weidong@zte.com.cn; lkml
> <linux-kernel@vger.kernel.org>; julia.lawall@lip6.fr; linuxppc-dev
> <linuxppc-dev@lists.ozlabs.org>; wen.yang99@zte.com.cn; moderated
> list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE
> <linux-arm-kernel@lists.infradead.org>
> Subject: Re: [PATCH] soc/fsl/qe: fix err handling of ucc_of_parse_tdm
> 
> On Thu, Nov 22, 2018 at 2:42 PM Yi Wang <wang.yi59@zte.com.cn> wrote:
> >
> > From: Wen Yang <wen.yang99@zte.com.cn>
> >
> > Currently there are 2 problems with the ucc_of_parse_tdm function:
> > 1,a possible null pointer dereference in ucc_of_parse_tdm, detected by
> > the semantic patch deref_null.cocci, with the following warning:
> > drivers/soc/fsl/qe/qe_tdm.c:177:21-24: ERROR: pdev is NULL but
> dereferenced.
> > 2,dev gets modified, so in any case that devm_iounmap() will fail even
> > when the new pdev is valid, because the iomap was done with a different
> pdev.
> > This patch fixes them.
> 
> While we are at this, I think this logic need more serious fixing.  I see there is
> no driver bind with the "fsl,t1040-qe-si" or "fsl,t1040-qe-siram" device.  So
> allocating resources using devm_*() with these devices won't provide a
> cleanup path for these resources when the caller fails.  I think we should
> probably allocate resource under device of caller (e.g. ucc-hdlc), so that when
> caller probe fails or is removed it will trigger the cleanup.
> 
> >
> > Suggested-by: Christophe LEROY <christophe.leroy@c-s.fr>
> > Signed-off-by: Wen Yang <wen.yang99@zte.com.cn>
> > CC: Julia Lawall <julia.lawall@lip6.fr>
> > CC: Zhao Qiang <qiang.zhao@nxp.com>
> > ---
> >  drivers/soc/fsl/qe/qe_tdm.c | 20 ++++++++++----------
> >  1 file changed, 10 insertions(+), 10 deletions(-)
> >
> > diff --git a/drivers/soc/fsl/qe/qe_tdm.c b/drivers/soc/fsl/qe/qe_tdm.c
> > index f78c346..9a29f0b 100644
> > --- a/drivers/soc/fsl/qe/qe_tdm.c
> > +++ b/drivers/soc/fsl/qe/qe_tdm.c
> > @@ -47,7 +47,7 @@ int ucc_of_parse_tdm(struct device_node *np, struct
> ucc_tdm *utdm,
> >         struct resource *res;
> >         struct device_node *np2;
> >         static int siram_init_flag;
> > -       struct platform_device *pdev;
> > +       struct platform_device *pdev_si, *pdev_siram;
> >
> >         sprop = of_get_property(np, "fsl,rx-sync-clock", NULL);
> >         if (sprop) {
> > @@ -129,16 +129,16 @@ int ucc_of_parse_tdm(struct device_node *np,
> struct ucc_tdm *utdm,
> >         if (!np2)
> >                 return -EINVAL;
> >
> > -       pdev = of_find_device_by_node(np2);
> > -       if (!pdev) {
> > +       pdev_si = of_find_device_by_node(np2);
> > +       if (!pdev_si) {
> >                 pr_err("%pOFn: failed to lookup pdev\n", np2);
> >                 of_node_put(np2);
> >                 return -EINVAL;
> >         }
> >
> >         of_node_put(np2);
> > -       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > -       utdm->si_regs = devm_ioremap_resource(&pdev->dev, res);
> > +       res = platform_get_resource(pdev_si, IORESOURCE_MEM, 0);
> > +       utdm->si_regs = devm_ioremap_resource(&pdev_si->dev, res);
> >         if (IS_ERR(utdm->si_regs)) {
> >                 ret = PTR_ERR(utdm->si_regs);
> >                 goto err_miss_siram_property; @@ -150,8 +150,8 @@
> int
> > ucc_of_parse_tdm(struct device_node *np, struct ucc_tdm *utdm,
> >                 goto err_miss_siram_property;
> >         }
> >
> > -       pdev = of_find_device_by_node(np2);
> > -       if (!pdev) {
> > +       pdev_siram = of_find_device_by_node(np2);
> > +       if (!pdev_siram) {
> >                 ret = -EINVAL;
> >                 pr_err("%pOFn: failed to lookup pdev\n", np2);
> >                 of_node_put(np2);
> > @@ -159,8 +159,8 @@ int ucc_of_parse_tdm(struct device_node *np, struct
> ucc_tdm *utdm,
> >         }
> >
> >         of_node_put(np2);
> > -       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > -       utdm->siram = devm_ioremap_resource(&pdev->dev, res);
> > +       res = platform_get_resource(pdev_siram, IORESOURCE_MEM, 0);
> > +       utdm->siram = devm_ioremap_resource(&pdev_siram->dev, res);
> >         if (IS_ERR(utdm->siram)) {
> >                 ret = PTR_ERR(utdm->siram);
> >                 goto err_miss_siram_property; @@ -174,7 +174,7 @@
> int
> > ucc_of_parse_tdm(struct device_node *np, struct ucc_tdm *utdm,
> >         return ret;
> >
> >  err_miss_siram_property:
> > -       devm_iounmap(&pdev->dev, utdm->si_regs);
> > +       devm_iounmap(&pdev_si->dev, utdm->si_regs);
> >         return ret;
> >  }
> >  EXPORT_SYMBOL(ucc_of_parse_tdm);
> > --
> > 2.9.5
> >