[PATCH] mfd: stmfx: Uninitialized variable in stmfx_irq_handler()

[PATCH] mfd: stmfx: Uninitialized variable in stmfx_irq_handler()

[Dan Carpenter]

The problem is that on 64bit systems then we don't clear the higher
bits of the "pending" variable.  So when we do:

	ack = pending & ~BIT(STMFX_REG_IRQ_SRC_EN_GPIO);
	if (ack) {

the if (ack) condition relies on uninitialized data.  The fix it that
I've changed "pending" from an unsigned long to a u32.  I changed "n" as
well, because that's a number in the 0-10 range and it fits easily
inside an int.  We do need to add a cast to "pending" when we use it in
the for_each_set_bit() loop, but that doesn't cause a proble, it's
fine.

Fixes: 06252ade9156 ("mfd: Add ST Multi-Function eXpander (STMFX) core driver")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
 drivers/mfd/stmfx.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/mfd/stmfx.c b/drivers/mfd/stmfx.c
index fe8efba2d45f..fee75b5d098e 100644
--- a/drivers/mfd/stmfx.c
+++ b/drivers/mfd/stmfx.c
@@ -204,12 +204,12 @@ static struct irq_chip stmfx_irq_chip = {
 static irqreturn_t stmfx_irq_handler(int irq, void *data)
 {
 	struct stmfx *stmfx = data;
-	unsigned long n, pending;
+	u32 pending;
 	u32 ack;
+	int n;
 	int ret;
 
-	ret = regmap_read(stmfx->map, STMFX_REG_IRQ_PENDING,
-			  (u32 *)&pending);
+	ret = regmap_read(stmfx->map, STMFX_REG_IRQ_PENDING, &pending);
 	if (ret)
 		return IRQ_NONE;
 
@@ -224,7 +224,7 @@ static irqreturn_t stmfx_irq_handler(int irq, void *data)
 			return IRQ_NONE;
 	}
 
-	for_each_set_bit(n, &pending, STMFX_REG_IRQ_SRC_MAX)
+	for_each_set_bit(n, (unsigned long *)&pending, STMFX_REG_IRQ_SRC_MAX)
 		handle_nested_irq(irq_find_mapping(stmfx->irq_domain, n));
 
 	return IRQ_HANDLED;
-- 
2.20.1

Re: [PATCH] mfd: stmfx: Uninitialized variable in stmfx_irq_handler()

[Lee Jones]

On Wed, 15 May 2019, Dan Carpenter wrote:

> The problem is that on 64bit systems then we don't clear the higher
> bits of the "pending" variable.  So when we do:
> 
> 	ack = pending & ~BIT(STMFX_REG_IRQ_SRC_EN_GPIO);
> 	if (ack) {
> 
> the if (ack) condition relies on uninitialized data.  The fix it that
> I've changed "pending" from an unsigned long to a u32.  I changed "n" as
> well, because that's a number in the 0-10 range and it fits easily
> inside an int.  We do need to add a cast to "pending" when we use it in
> the for_each_set_bit() loop, but that doesn't cause a proble, it's
> fine.
> 
> Fixes: 06252ade9156 ("mfd: Add ST Multi-Function eXpander (STMFX) core driver")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
>  drivers/mfd/stmfx.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)

Could do with an author's Ack here.

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH] mfd: stmfx: Uninitialized variable in stmfx_irq_handler()

[Amelie DELAUNAY]

Hi Dan,

Thanks for your patch. One minor comment:

On 5/15/19 11:31 AM, Dan Carpenter wrote:
> The problem is that on 64bit systems then we don't clear the higher
> bits of the "pending" variable.  So when we do:
> 
> 	ack = pending & ~BIT(STMFX_REG_IRQ_SRC_EN_GPIO);
> 	if (ack) {
> 
> the if (ack) condition relies on uninitialized data.  The fix it that
> I've changed "pending" from an unsigned long to a u32.  I changed "n" as
> well, because that's a number in the 0-10 range and it fits easily
> inside an int.  We do need to add a cast to "pending" when we use it in
> the for_each_set_bit() loop, but that doesn't cause a proble, it's
> fine.
> 
> Fixes: 06252ade9156 ("mfd: Add ST Multi-Function eXpander (STMFX) core driver")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
>   drivers/mfd/stmfx.c | 8 ++++----
>   1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/mfd/stmfx.c b/drivers/mfd/stmfx.c
> index fe8efba2d45f..fee75b5d098e 100644
> --- a/drivers/mfd/stmfx.c
> +++ b/drivers/mfd/stmfx.c
> @@ -204,12 +204,12 @@ static struct irq_chip stmfx_irq_chip = {
>   static irqreturn_t stmfx_irq_handler(int irq, void *data)
>   {
>   	struct stmfx *stmfx = data;
> -	unsigned long n, pending;
> +	u32 pending;
>   	u32 ack;
> +	int n;
>   	int ret;

Could you group:

u32 pending, ack;
int n, ret;

>   
> -	ret = regmap_read(stmfx->map, STMFX_REG_IRQ_PENDING,
> -			  (u32 *)&pending);
> +	ret = regmap_read(stmfx->map, STMFX_REG_IRQ_PENDING, &pending);
>   	if (ret)
>   		return IRQ_NONE;
>   
> @@ -224,7 +224,7 @@ static irqreturn_t stmfx_irq_handler(int irq, void *data)
>   			return IRQ_NONE;
>   	}
>   
> -	for_each_set_bit(n, &pending, STMFX_REG_IRQ_SRC_MAX)
> +	for_each_set_bit(n, (unsigned long *)&pending, STMFX_REG_IRQ_SRC_MAX)
>   		handle_nested_irq(irq_find_mapping(stmfx->irq_domain, n));
>   
>   	return IRQ_HANDLED;
> 

I've tested it on stm32mp157c-ev1, so you can add my
Tested-by: Amelie Delaunay <amelie.delaunay@st.com>

Regards,
Amelie

[PATCH v2] mfd: stmfx: Uninitialized variable in stmfx_irq_handler()

[Dan Carpenter]

The problem is that on 64bit systems then we don't clear the higher
bits of the "pending" variable.  So when we do:

        ack = pending & ~BIT(STMFX_REG_IRQ_SRC_EN_GPIO);
        if (ack) {

the if (ack) condition relies on uninitialized data.  The fix it that
I've changed "pending" from an unsigned long to a u32.  I changed "n" as
well, because that's a number in the 0-10 range and it fits easily
inside an int.  We do need to add a cast to "pending" when we use it in
the for_each_set_bit() loop, but that doesn't cause a proble, it's
fine.

Fixes: 06252ade9156 ("mfd: Add ST Multi-Function eXpander (STMFX) core driver")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
v2: white space changes

 drivers/mfd/stmfx.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/drivers/mfd/stmfx.c b/drivers/mfd/stmfx.c
index fe8efba2d45f..7c419c078688 100644
--- a/drivers/mfd/stmfx.c
+++ b/drivers/mfd/stmfx.c
@@ -204,12 +204,10 @@ static struct irq_chip stmfx_irq_chip = {
 static irqreturn_t stmfx_irq_handler(int irq, void *data)
 {
 	struct stmfx *stmfx = data;
-	unsigned long n, pending;
-	u32 ack;
-	int ret;
+	u32 pending, ack;
+	int n, ret;
 
-	ret = regmap_read(stmfx->map, STMFX_REG_IRQ_PENDING,
-			  (u32 *)&pending);
+	ret = regmap_read(stmfx->map, STMFX_REG_IRQ_PENDING, &pending);
 	if (ret)
 		return IRQ_NONE;
 
@@ -224,7 +222,7 @@ static irqreturn_t stmfx_irq_handler(int irq, void *data)
 			return IRQ_NONE;
 	}
 
-	for_each_set_bit(n, &pending, STMFX_REG_IRQ_SRC_MAX)
+	for_each_set_bit(n, (unsigned long *)&pending, STMFX_REG_IRQ_SRC_MAX)
 		handle_nested_irq(irq_find_mapping(stmfx->irq_domain, n));
 
 	return IRQ_HANDLED;
-- 
2.20.1

Re: [PATCH v2] mfd: stmfx: Uninitialized variable in stmfx_irq_handler()

[Amelie DELAUNAY]

On 6/6/19 2:41 PM, Dan Carpenter wrote:
> The problem is that on 64bit systems then we don't clear the higher
> bits of the "pending" variable.  So when we do:
> 
>          ack = pending & ~BIT(STMFX_REG_IRQ_SRC_EN_GPIO);
>          if (ack) {
> 
> the if (ack) condition relies on uninitialized data.  The fix it that
> I've changed "pending" from an unsigned long to a u32.  I changed "n" as
> well, because that's a number in the 0-10 range and it fits easily
> inside an int.  We do need to add a cast to "pending" when we use it in
> the for_each_set_bit() loop, but that doesn't cause a proble, it's
> fine.
> 
> Fixes: 06252ade9156 ("mfd: Add ST Multi-Function eXpander (STMFX) core driver")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

Acked-by: Amelie Delaunay <amelie.delaunay@st.com>

> ---
> v2: white space changes
> 
>   drivers/mfd/stmfx.c | 10 ++++------
>   1 file changed, 4 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/mfd/stmfx.c b/drivers/mfd/stmfx.c
> index fe8efba2d45f..7c419c078688 100644
> --- a/drivers/mfd/stmfx.c
> +++ b/drivers/mfd/stmfx.c
> @@ -204,12 +204,10 @@ static struct irq_chip stmfx_irq_chip = {
>   static irqreturn_t stmfx_irq_handler(int irq, void *data)
>   {
>   	struct stmfx *stmfx = data;
> -	unsigned long n, pending;
> -	u32 ack;
> -	int ret;
> +	u32 pending, ack;
> +	int n, ret;
>   
> -	ret = regmap_read(stmfx->map, STMFX_REG_IRQ_PENDING,
> -			  (u32 *)&pending);
> +	ret = regmap_read(stmfx->map, STMFX_REG_IRQ_PENDING, &pending);
>   	if (ret)
>   		return IRQ_NONE;
>   
> @@ -224,7 +222,7 @@ static irqreturn_t stmfx_irq_handler(int irq, void *data)
>   			return IRQ_NONE;
>   	}
>   
> -	for_each_set_bit(n, &pending, STMFX_REG_IRQ_SRC_MAX)
> +	for_each_set_bit(n, (unsigned long *)&pending, STMFX_REG_IRQ_SRC_MAX)
>   		handle_nested_irq(irq_find_mapping(stmfx->irq_domain, n));
>   
>   	return IRQ_HANDLED;
> 

Re: [PATCH v2] mfd: stmfx: Uninitialized variable in stmfx_irq_handler()

[Lee Jones]

On Thu, 06 Jun 2019, Dan Carpenter wrote:

> The problem is that on 64bit systems then we don't clear the higher
> bits of the "pending" variable.  So when we do:
> 
>         ack = pending & ~BIT(STMFX_REG_IRQ_SRC_EN_GPIO);
>         if (ack) {
> 
> the if (ack) condition relies on uninitialized data.  The fix it that
> I've changed "pending" from an unsigned long to a u32.  I changed "n" as
> well, because that's a number in the 0-10 range and it fits easily
> inside an int.  We do need to add a cast to "pending" when we use it in
> the for_each_set_bit() loop, but that doesn't cause a proble, it's
> fine.
> 
> Fixes: 06252ade9156 ("mfd: Add ST Multi-Function eXpander (STMFX) core driver")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
> v2: white space changes
> 
>  drivers/mfd/stmfx.c | 10 ++++------
>  1 file changed, 4 insertions(+), 6 deletions(-)

Applied, thanks.

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog