* [PATCH 0/2] clk: Do not register provider with a NULL dev->of_node
@ 2021-04-23 17:13 Tudor Ambarus
2021-04-23 17:13 ` [PATCH 1/2] " Tudor Ambarus
` (2 more replies)
0 siblings, 3 replies; 9+ messages in thread
From: Tudor Ambarus @ 2021-04-23 17:13 UTC (permalink / raw)
To: mturquette, sboyd, nsaenz, maxime, gregkh, rafael, khilman,
ulf.hansson, len.brown, pavel, robh+dt, frowand.list, maz, tglx,
saravanak, geert, nsaenzjulienne, linux, guillaume.tucker
Cc: linux-clk, linux-kernel, corbet, nicolas.ferre, claudiu.beznea,
linux-doc, linux-pm, devicetree, linux-acpi, kernel-team,
linux-rpi-kernel, Tudor Ambarus
This fixes a NULL pointer dereference that was revealed by
commit 6579c8d97ad7 ("clk: Mark fwnodes when their clock provider is added")
I chose to just return -ENODEV when a driver calls devm_of_clk_add_hw_provider()
with a NULL dev->of_node, because it seems natural to return a failure when one
asks for an _of_ function to do something, but by providing with a NULL of_node.
Plus, it avoids some waste of memory, as the call to devres_alloc() will not
take place.
The opinions on how to handle this NULL pointer dereference were split, either
by returning an error when one calls devm_of_clk_add_hw_provider() with a NULL
dev->of_node, as I did, or by
return 0 in of_clk_add_hw_provider() when np == NULL and
return 0 in of_clk_del_provider() when np == NULL.
Let me know if you prefer the second approach.
Compile tested only.
Tudor Ambarus (2):
clk: Do not register provider with a NULL dev->of_node
clk: bcm: rpi: Do not call devm_of_clk_add_hw_provider with a NULL
dev->of_node
drivers/clk/bcm/clk-raspberrypi.c | 10 ++++++----
drivers/clk/clk.c | 12 +++++++-----
2 files changed, 13 insertions(+), 9 deletions(-)
--
2.25.1
^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCH 1/2] clk: Do not register provider with a NULL dev->of_node
2021-04-23 17:13 [PATCH 0/2] clk: Do not register provider with a NULL dev->of_node Tudor Ambarus
@ 2021-04-23 17:13 ` Tudor Ambarus
2021-04-23 17:24 ` Saravana Kannan
2021-04-23 17:13 ` [PATCH 2/2] clk: bcm: rpi: Do not call devm_of_clk_add_hw_provider " Tudor Ambarus
2021-04-23 19:12 ` [PATCH] clk: Skip clk provider registration when np is NULL Tudor Ambarus
2 siblings, 1 reply; 9+ messages in thread
From: Tudor Ambarus @ 2021-04-23 17:13 UTC (permalink / raw)
To: mturquette, sboyd, nsaenz, maxime, gregkh, rafael, khilman,
ulf.hansson, len.brown, pavel, robh+dt, frowand.list, maz, tglx,
saravanak, geert, nsaenzjulienne, linux, guillaume.tucker
Cc: linux-clk, linux-kernel, corbet, nicolas.ferre, claudiu.beznea,
linux-doc, linux-pm, devicetree, linux-acpi, kernel-team,
linux-rpi-kernel, Tudor Ambarus, Marek Szyprowski
commit 6579c8d97ad7 ("clk: Mark fwnodes when their clock provider is added")
revealed that clk/bcm/clk-raspberrypi.c driver calls
devm_of_clk_add_hw_provider(), with a NULL dev->of_node.
devm_of_clk_add_hw_provider() should not register the provider with
a NULL dev->of_node, as there is no of_node. Apart of the NULL pointer
dereference that will result when calling fwnode_dev_initialized() in
of_clk_add_hw_provider(), another problem is that when two drivers calling
of_clk_add_hw_provider() with np = NULL, their unregistration order is not
guaranteed to be correct. Avoid all the problems and just return -ENODEV
when the callers of devm_of_clk_add_hw_provider() use a NULL dev->of_node,
which seems the natural way to do.
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Fixes: 6579c8d97ad7 ("clk: Mark fwnodes when their clock provider is added")
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
---
drivers/clk/clk.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index e2ec1b745243..8b5077cc5e67 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -4634,11 +4634,10 @@ static struct device_node *get_clk_provider_node(struct device *dev)
* @get: callback for decoding clk_hw
* @data: context pointer for @get callback
*
- * Registers clock provider for given device's node. If the device has no DT
- * node or if the device node lacks of clock provider information (#clock-cells)
- * then the parent device's node is scanned for this information. If parent node
- * has the #clock-cells then it is used in registration. Provider is
- * automatically released at device exit.
+ * Registers clock provider for given device's node. If the device node lacks
+ * of clock provider information (#clock-cells) then the parent device's node is
+ * scanned for this information. If parent node has the #clock-cells then it is
+ * used in registration. Provider is automatically released at device exit.
*
* Return: 0 on success or an errno on failure.
*/
@@ -4650,6 +4649,9 @@ int devm_of_clk_add_hw_provider(struct device *dev,
struct device_node **ptr, *np;
int ret;
+ if (!dev->of_node)
+ return -ENODEV;
+
ptr = devres_alloc(devm_of_clk_release_provider, sizeof(*ptr),
GFP_KERNEL);
if (!ptr)
--
2.25.1
^ permalink raw reply related [flat|nested] 9+ messages in thread
* [PATCH 2/2] clk: bcm: rpi: Do not call devm_of_clk_add_hw_provider with a NULL dev->of_node
2021-04-23 17:13 [PATCH 0/2] clk: Do not register provider with a NULL dev->of_node Tudor Ambarus
2021-04-23 17:13 ` [PATCH 1/2] " Tudor Ambarus
@ 2021-04-23 17:13 ` Tudor Ambarus
2021-04-23 19:12 ` [PATCH] clk: Skip clk provider registration when np is NULL Tudor Ambarus
2 siblings, 0 replies; 9+ messages in thread
From: Tudor Ambarus @ 2021-04-23 17:13 UTC (permalink / raw)
To: mturquette, sboyd, nsaenz, maxime, gregkh, rafael, khilman,
ulf.hansson, len.brown, pavel, robh+dt, frowand.list, maz, tglx,
saravanak, geert, nsaenzjulienne, linux, guillaume.tucker
Cc: linux-clk, linux-kernel, corbet, nicolas.ferre, claudiu.beznea,
linux-doc, linux-pm, devicetree, linux-acpi, kernel-team,
linux-rpi-kernel, Tudor Ambarus, Marek Szyprowski
devm_of_clk_add_hw_provider() expects, as the "_of_" string indicates,
a non NULL dev->of_node, otherwise it will return -ENODEV.
Since this driver can be probed either through the old-fashioned
platform device registration or through a DT node that is a child of the
firmware node, call devm_of_clk_add_hw_provider() only when the DT node
is present.
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Fixes: 6579c8d97ad7 ("clk: Mark fwnodes when their clock provider is added")
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
---
drivers/clk/bcm/clk-raspberrypi.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/drivers/clk/bcm/clk-raspberrypi.c b/drivers/clk/bcm/clk-raspberrypi.c
index dd3b71eafabf..84a4e14babff 100644
--- a/drivers/clk/bcm/clk-raspberrypi.c
+++ b/drivers/clk/bcm/clk-raspberrypi.c
@@ -337,10 +337,12 @@ static int raspberrypi_clk_probe(struct platform_device *pdev)
if (ret)
return ret;
- ret = devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get,
- clk_data);
- if (ret)
- return ret;
+ if (dev->of_node) {
+ ret = devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get,
+ clk_data);
+ if (ret)
+ return ret;
+ }
rpi->cpufreq = platform_device_register_data(dev, "raspberrypi-cpufreq",
-1, NULL, 0);
--
2.25.1
^ permalink raw reply related [flat|nested] 9+ messages in thread
* Re: [PATCH 1/2] clk: Do not register provider with a NULL dev->of_node
2021-04-23 17:13 ` [PATCH 1/2] " Tudor Ambarus
@ 2021-04-23 17:24 ` Saravana Kannan
2021-04-23 18:21 ` nicolas saenz julienne
0 siblings, 1 reply; 9+ messages in thread
From: Saravana Kannan @ 2021-04-23 17:24 UTC (permalink / raw)
To: Tudor Ambarus
Cc: mturquette, sboyd, nsaenz, maxime, gregkh, rafael, khilman,
ulf.hansson, len.brown, pavel, robh+dt, frowand.list, maz, tglx,
geert, nsaenzjulienne, linux, guillaume.tucker, linux-clk,
linux-kernel, corbet, nicolas.ferre, claudiu.beznea, linux-doc,
linux-pm, devicetree, linux-acpi, kernel-team, linux-rpi-kernel,
Marek Szyprowski
On Fri, Apr 23, 2021 at 10:14 AM Tudor Ambarus
<tudor.ambarus@microchip.com> wrote:
>
> commit 6579c8d97ad7 ("clk: Mark fwnodes when their clock provider is added")
> revealed that clk/bcm/clk-raspberrypi.c driver calls
> devm_of_clk_add_hw_provider(), with a NULL dev->of_node.
>
> devm_of_clk_add_hw_provider() should not register the provider with
> a NULL dev->of_node, as there is no of_node. Apart of the NULL pointer
> dereference that will result when calling fwnode_dev_initialized() in
> of_clk_add_hw_provider(), another problem is that when two drivers calling
> of_clk_add_hw_provider() with np = NULL, their unregistration order is not
> guaranteed to be correct. Avoid all the problems and just return -ENODEV
> when the callers of devm_of_clk_add_hw_provider() use a NULL dev->of_node,
> which seems the natural way to do.
>
> Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
> Fixes: 6579c8d97ad7 ("clk: Mark fwnodes when their clock provider is added")
> Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
> ---
> drivers/clk/clk.c | 12 +++++++-----
> 1 file changed, 7 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> index e2ec1b745243..8b5077cc5e67 100644
> --- a/drivers/clk/clk.c
> +++ b/drivers/clk/clk.c
> @@ -4634,11 +4634,10 @@ static struct device_node *get_clk_provider_node(struct device *dev)
> * @get: callback for decoding clk_hw
> * @data: context pointer for @get callback
> *
> - * Registers clock provider for given device's node. If the device has no DT
> - * node or if the device node lacks of clock provider information (#clock-cells)
> - * then the parent device's node is scanned for this information. If parent node
> - * has the #clock-cells then it is used in registration. Provider is
> - * automatically released at device exit.
> + * Registers clock provider for given device's node. If the device node lacks
> + * of clock provider information (#clock-cells) then the parent device's node is
> + * scanned for this information. If parent node has the #clock-cells then it is
> + * used in registration. Provider is automatically released at device exit.
> *
> * Return: 0 on success or an errno on failure.
> */
> @@ -4650,6 +4649,9 @@ int devm_of_clk_add_hw_provider(struct device *dev,
> struct device_node **ptr, *np;
> int ret;
>
> + if (!dev->of_node)
> + return -ENODEV;
> +
Based on the other discussions, for now, just return 0. The error
might cause other issues in other drivers. We can clean this up later.
-Saravana
> ptr = devres_alloc(devm_of_clk_release_provider, sizeof(*ptr),
> GFP_KERNEL);
> if (!ptr)
> --
> 2.25.1
>
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH 1/2] clk: Do not register provider with a NULL dev->of_node
2021-04-23 17:24 ` Saravana Kannan
@ 2021-04-23 18:21 ` nicolas saenz julienne
2021-04-23 18:35 ` Tudor.Ambarus
0 siblings, 1 reply; 9+ messages in thread
From: nicolas saenz julienne @ 2021-04-23 18:21 UTC (permalink / raw)
To: Saravana Kannan, Tudor Ambarus
Cc: mturquette, sboyd, maxime, gregkh, rafael, khilman, ulf.hansson,
len.brown, pavel, robh+dt, frowand.list, maz, tglx, geert,
nsaenzjulienne, linux, guillaume.tucker, linux-clk, linux-kernel,
corbet, nicolas.ferre, claudiu.beznea, linux-doc, linux-pm,
devicetree, linux-acpi, kernel-team, linux-rpi-kernel,
Marek Szyprowski
Hi Saravana, Tudor,
On Fri, 2021-04-23 at 10:24 -0700, Saravana Kannan wrote:
> On Fri, Apr 23, 2021 at 10:14 AM Tudor Ambarus
> <tudor.ambarus@microchip.com> wrote:
> >
> > commit 6579c8d97ad7 ("clk: Mark fwnodes when their clock provider is added")
> > revealed that clk/bcm/clk-raspberrypi.c driver calls
> > devm_of_clk_add_hw_provider(), with a NULL dev->of_node.
> >
> > devm_of_clk_add_hw_provider() should not register the provider with
> > a NULL dev->of_node, as there is no of_node. Apart of the NULL pointer
> > dereference that will result when calling fwnode_dev_initialized() in
> > of_clk_add_hw_provider(), another problem is that when two drivers calling
> > of_clk_add_hw_provider() with np = NULL, their unregistration order is not
> > guaranteed to be correct. Avoid all the problems and just return -ENODEV
> > when the callers of devm_of_clk_add_hw_provider() use a NULL dev->of_node,
> > which seems the natural way to do.
> >
> > Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
> > Fixes: 6579c8d97ad7 ("clk: Mark fwnodes when their clock provider is added")
> > Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
> > ---
> > drivers/clk/clk.c | 12 +++++++-----
> > 1 file changed, 7 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> > index e2ec1b745243..8b5077cc5e67 100644
> > --- a/drivers/clk/clk.c
> > +++ b/drivers/clk/clk.c
> > @@ -4634,11 +4634,10 @@ static struct device_node *get_clk_provider_node(struct device *dev)
> > * @get: callback for decoding clk_hw
> > * @data: context pointer for @get callback
> > *
> > - * Registers clock provider for given device's node. If the device has no DT
> > - * node or if the device node lacks of clock provider information (#clock-cells)
> > - * then the parent device's node is scanned for this information. If parent node
> > - * has the #clock-cells then it is used in registration. Provider is
> > - * automatically released at device exit.
> > + * Registers clock provider for given device's node. If the device node lacks
> > + * of clock provider information (#clock-cells) then the parent device's node is
> > + * scanned for this information. If parent node has the #clock-cells then it is
> > + * used in registration. Provider is automatically released at device exit.
> > *
> > * Return: 0 on success or an errno on failure.
> > */
> > @@ -4650,6 +4649,9 @@ int devm_of_clk_add_hw_provider(struct device *dev,
> > struct device_node **ptr, *np;
> > int ret;
> >
> > + if (!dev->of_node)
> > + return -ENODEV;
> > +
>
> Based on the other discussions, for now, just return 0. The error
> might cause other issues in other drivers. We can clean this up later.
+1, Let's return 0 and do nothing skip the logic in the driver.
Now, from what I read in devm_of_clk_add_hw_provider(), there is a use case for
entering with '!dev->of_node'. See get_clk_provider_node()'s usage. So I think
we should only bail if that function fails to provide a device_node.
Regards,
Nicolas
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH 1/2] clk: Do not register provider with a NULL dev->of_node
2021-04-23 18:21 ` nicolas saenz julienne
@ 2021-04-23 18:35 ` Tudor.Ambarus
0 siblings, 0 replies; 9+ messages in thread
From: Tudor.Ambarus @ 2021-04-23 18:35 UTC (permalink / raw)
To: nsaenz, saravanak
Cc: mturquette, sboyd, maxime, gregkh, rafael, khilman, ulf.hansson,
len.brown, pavel, robh+dt, frowand.list, maz, tglx, geert,
nsaenzjulienne, linux, guillaume.tucker, linux-clk, linux-kernel,
corbet, Nicolas.Ferre, Claudiu.Beznea, linux-doc, linux-pm,
devicetree, linux-acpi, kernel-team, linux-rpi-kernel,
m.szyprowski
On 4/23/21 9:21 PM, nicolas saenz julienne wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>
> Hi Saravana, Tudor,
>
> On Fri, 2021-04-23 at 10:24 -0700, Saravana Kannan wrote:
>> On Fri, Apr 23, 2021 at 10:14 AM Tudor Ambarus
>> <tudor.ambarus@microchip.com> wrote:
>>>
>>> commit 6579c8d97ad7 ("clk: Mark fwnodes when their clock provider is added")
>>> revealed that clk/bcm/clk-raspberrypi.c driver calls
>>> devm_of_clk_add_hw_provider(), with a NULL dev->of_node.
>>>
>>> devm_of_clk_add_hw_provider() should not register the provider with
>>> a NULL dev->of_node, as there is no of_node. Apart of the NULL pointer
>>> dereference that will result when calling fwnode_dev_initialized() in
>>> of_clk_add_hw_provider(), another problem is that when two drivers calling
>>> of_clk_add_hw_provider() with np = NULL, their unregistration order is not
>>> guaranteed to be correct. Avoid all the problems and just return -ENODEV
>>> when the callers of devm_of_clk_add_hw_provider() use a NULL dev->of_node,
>>> which seems the natural way to do.
>>>
>>> Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
>>> Fixes: 6579c8d97ad7 ("clk: Mark fwnodes when their clock provider is added")
>>> Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
>>> ---
>>> drivers/clk/clk.c | 12 +++++++-----
>>> 1 file changed, 7 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
>>> index e2ec1b745243..8b5077cc5e67 100644
>>> --- a/drivers/clk/clk.c
>>> +++ b/drivers/clk/clk.c
>>> @@ -4634,11 +4634,10 @@ static struct device_node *get_clk_provider_node(struct device *dev)
>>> * @get: callback for decoding clk_hw
>>> * @data: context pointer for @get callback
>>> *
>>> - * Registers clock provider for given device's node. If the device has no DT
>>> - * node or if the device node lacks of clock provider information (#clock-cells)
>>> - * then the parent device's node is scanned for this information. If parent node
>>> - * has the #clock-cells then it is used in registration. Provider is
>>> - * automatically released at device exit.
>>> + * Registers clock provider for given device's node. If the device node lacks
>>> + * of clock provider information (#clock-cells) then the parent device's node is
>>> + * scanned for this information. If parent node has the #clock-cells then it is
>>> + * used in registration. Provider is automatically released at device exit.
>>> *
>>> * Return: 0 on success or an errno on failure.
>>> */
>>> @@ -4650,6 +4649,9 @@ int devm_of_clk_add_hw_provider(struct device *dev,
>>> struct device_node **ptr, *np;
>>> int ret;
>>>
>>> + if (!dev->of_node)
>>> + return -ENODEV;
>>> +
>>
>> Based on the other discussions, for now, just return 0. The error
>> might cause other issues in other drivers. We can clean this up later.
>
> +1, Let's return 0 and do nothing skip the logic in the driver.
>
> Now, from what I read in devm_of_clk_add_hw_provider(), there is a use case for
> entering with '!dev->of_node'. See get_clk_provider_node()'s usage. So I think
> we should only bail if that function fails to provide a device_node.
>
Oh, yes, the error should have been after the get_clk_provider_node().
Any way, will send the return 0 variant too.
Cheers,
ta
^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCH] clk: Skip clk provider registration when np is NULL
2021-04-23 17:13 [PATCH 0/2] clk: Do not register provider with a NULL dev->of_node Tudor Ambarus
2021-04-23 17:13 ` [PATCH 1/2] " Tudor Ambarus
2021-04-23 17:13 ` [PATCH 2/2] clk: bcm: rpi: Do not call devm_of_clk_add_hw_provider " Tudor Ambarus
@ 2021-04-23 19:12 ` Tudor Ambarus
2021-04-23 19:16 ` Tudor.Ambarus
2021-04-24 1:17 ` Stephen Boyd
2 siblings, 2 replies; 9+ messages in thread
From: Tudor Ambarus @ 2021-04-23 19:12 UTC (permalink / raw)
To: mturquette, sboyd, nsaenz, maxime, gregkh, rafael, khilman,
ulf.hansson, len.brown, pavel, robh+dt, frowand.list, maz, tglx,
saravanak, geert, nsaenzjulienne, linux, guillaume.tucker
Cc: linux-clk, linux-kernel, corbet, nicolas.ferre, claudiu.beznea,
linux-doc, linux-pm, devicetree, linux-acpi, kernel-team,
linux-rpi-kernel, Tudor Ambarus, Marek Szyprowski
commit 6579c8d97ad7 ("clk: Mark fwnodes when their clock provider is added")
revealed that clk/bcm/clk-raspberrypi.c driver calls
devm_of_clk_add_hw_provider(), with a NULL dev->of_node, which resulted in a
NULL pointer dereference in of_clk_add_provider() when calling
fwnode_dev_initialized().
Returning 0 is reducing the if conditions in driver code and is being
consistent with the CONFIG_OF=n inline stub that returns 0 when CONFIG_OF
is disabled. The downside is that drivers will maybe register clkdev lookups
when they don't need to and waste some memory.
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Fixes: 6579c8d97ad7 ("clk: Mark fwnodes when their clock provider is added")
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
---
This would be the second approach, where we don't return an error when
one calls devm_of_clk_add_hw_provider with a NULL of_node, but instead
we just return 0 and skip the logic in the core and the drivers.
drivers/clk/clk.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index e2ec1b745243..5d10da3519ac 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -4540,6 +4540,9 @@ int of_clk_add_provider(struct device_node *np,
struct of_clk_provider *cp;
int ret;
+ if (!np)
+ return 0;
+
cp = kzalloc(sizeof(*cp), GFP_KERNEL);
if (!cp)
return -ENOMEM;
@@ -4579,6 +4582,9 @@ int of_clk_add_hw_provider(struct device_node *np,
struct of_clk_provider *cp;
int ret;
+ if (!np)
+ return 0;
+
cp = kzalloc(sizeof(*cp), GFP_KERNEL);
if (!cp)
return -ENOMEM;
@@ -4676,6 +4682,9 @@ void of_clk_del_provider(struct device_node *np)
{
struct of_clk_provider *cp;
+ if (!np)
+ return 0;
+
mutex_lock(&of_clk_mutex);
list_for_each_entry(cp, &of_clk_providers, link) {
if (cp->node == np) {
--
2.25.1
^ permalink raw reply related [flat|nested] 9+ messages in thread
* Re: [PATCH] clk: Skip clk provider registration when np is NULL
2021-04-23 19:12 ` [PATCH] clk: Skip clk provider registration when np is NULL Tudor Ambarus
@ 2021-04-23 19:16 ` Tudor.Ambarus
2021-04-24 1:17 ` Stephen Boyd
1 sibling, 0 replies; 9+ messages in thread
From: Tudor.Ambarus @ 2021-04-23 19:16 UTC (permalink / raw)
To: mturquette, sboyd, nsaenz, maxime, gregkh, rafael, khilman,
ulf.hansson, len.brown, pavel, robh+dt, frowand.list, maz, tglx,
saravanak, geert, nsaenzjulienne, linux, guillaume.tucker
Cc: linux-clk, linux-kernel, corbet, Nicolas.Ferre, Claudiu.Beznea,
linux-doc, linux-pm, devicetree, linux-acpi, kernel-team,
linux-rpi-kernel, m.szyprowski
On 4/23/21 10:12 PM, Tudor Ambarus wrote:
> commit 6579c8d97ad7 ("clk: Mark fwnodes when their clock provider is added")
> revealed that clk/bcm/clk-raspberrypi.c driver calls
> devm_of_clk_add_hw_provider(), with a NULL dev->of_node, which resulted in a
> NULL pointer dereference in of_clk_add_provider() when calling
s/of_clk_add_provider()/of_clk_add_hw_provider()
> fwnode_dev_initialized().
>
> Returning 0 is reducing the if conditions in driver code and is being
> consistent with the CONFIG_OF=n inline stub that returns 0 when CONFIG_OF
> is disabled. The downside is that drivers will maybe register clkdev lookups
> when they don't need to and waste some memory.
>
> Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
> Fixes: 6579c8d97ad7 ("clk: Mark fwnodes when their clock provider is added")
> Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
> ---
> This would be the second approach, where we don't return an error when
> one calls devm_of_clk_add_hw_provider with a NULL of_node, but instead
> we just return 0 and skip the logic in the core and the drivers.
>
> drivers/clk/clk.c | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> index e2ec1b745243..5d10da3519ac 100644
> --- a/drivers/clk/clk.c
> +++ b/drivers/clk/clk.c
> @@ -4540,6 +4540,9 @@ int of_clk_add_provider(struct device_node *np,
> struct of_clk_provider *cp;
> int ret;
>
> + if (!np)
> + return 0;
> +
> cp = kzalloc(sizeof(*cp), GFP_KERNEL);
> if (!cp)
> return -ENOMEM;
> @@ -4579,6 +4582,9 @@ int of_clk_add_hw_provider(struct device_node *np,
> struct of_clk_provider *cp;
> int ret;
>
> + if (!np)
> + return 0;
> +
> cp = kzalloc(sizeof(*cp), GFP_KERNEL);
> if (!cp)
> return -ENOMEM;
> @@ -4676,6 +4682,9 @@ void of_clk_del_provider(struct device_node *np)
> {
> struct of_clk_provider *cp;
>
> + if (!np)
> + return 0;
> +
> mutex_lock(&of_clk_mutex);
> list_for_each_entry(cp, &of_clk_providers, link) {
> if (cp->node == np) {
>
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] clk: Skip clk provider registration when np is NULL
2021-04-23 19:12 ` [PATCH] clk: Skip clk provider registration when np is NULL Tudor Ambarus
2021-04-23 19:16 ` Tudor.Ambarus
@ 2021-04-24 1:17 ` Stephen Boyd
1 sibling, 0 replies; 9+ messages in thread
From: Stephen Boyd @ 2021-04-24 1:17 UTC (permalink / raw)
To: Tudor Ambarus, frowand.list, geert, gregkh, guillaume.tucker,
khilman, len.brown, linux, maxime, maz, mturquette, nsaenz,
nsaenzjulienne, pavel, rafael, robh+dt, saravanak, tglx,
ulf.hansson
Cc: linux-clk, linux-kernel, corbet, nicolas.ferre, claudiu.beznea,
linux-doc, linux-pm, devicetree, linux-acpi, kernel-team,
linux-rpi-kernel, Tudor Ambarus, Marek Szyprowski
Quoting Tudor Ambarus (2021-04-23 12:12:36)
> commit 6579c8d97ad7 ("clk: Mark fwnodes when their clock provider is added")
> revealed that clk/bcm/clk-raspberrypi.c driver calls
> devm_of_clk_add_hw_provider(), with a NULL dev->of_node, which resulted in a
> NULL pointer dereference in of_clk_add_provider() when calling
> fwnode_dev_initialized().
>
> Returning 0 is reducing the if conditions in driver code and is being
> consistent with the CONFIG_OF=n inline stub that returns 0 when CONFIG_OF
> is disabled. The downside is that drivers will maybe register clkdev lookups
> when they don't need to and waste some memory.
>
> Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
> Fixes: 6579c8d97ad7 ("clk: Mark fwnodes when their clock provider is added")
> Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
> ---
Please don't send patches as replies to previous threads. It makes it
harder to find the patch at a glance of all threads.
It also seems to be a
Fixes: 3c9ea42802a1 ("clk: Mark fwnodes when their clock provider is added/removed")
so can you please have both Fixes tags?
> This would be the second approach, where we don't return an error when
> one calls devm_of_clk_add_hw_provider with a NULL of_node, but instead
> we just return 0 and skip the logic in the core and the drivers.
With the Fixes tag updated please send To: gregkh@ to pick up as the
problematic patch (6579c8d97ad7) is in the driver tree and not the clk
tree, and add my tag
Reviewed-by: Stephen Boyd <sboyd@kernel.org>
^ permalink raw reply [flat|nested] 9+ messages in thread
end of thread, other threads:[~2021-04-24 1:17 UTC | newest]
Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-04-23 17:13 [PATCH 0/2] clk: Do not register provider with a NULL dev->of_node Tudor Ambarus
2021-04-23 17:13 ` [PATCH 1/2] " Tudor Ambarus
2021-04-23 17:24 ` Saravana Kannan
2021-04-23 18:21 ` nicolas saenz julienne
2021-04-23 18:35 ` Tudor.Ambarus
2021-04-23 17:13 ` [PATCH 2/2] clk: bcm: rpi: Do not call devm_of_clk_add_hw_provider " Tudor Ambarus
2021-04-23 19:12 ` [PATCH] clk: Skip clk provider registration when np is NULL Tudor Ambarus
2021-04-23 19:16 ` Tudor.Ambarus
2021-04-24 1:17 ` Stephen Boyd
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