2020-10-22 18:54:09

by Andy Shevchenko

Subject: [PATCH v1 2/2] device property: Don't clear secondary pointer for shared primary firmware node

It appears that firmware nodes can be shared between devices. In such case
when a (child) device is about to be deleted, its firmware node may be shared
and ACPI_COMPANION_SET(..., NULL) call for it breaks the secondary link
of the shared primary firmware node.

In order to prevent that, check, if the device has a parent and parent's
firmware node is shared with its child, and avoid crashing the link.

Fixes: c15e1bdda436 ("device property: Fix the secondary firmware node handling in set_primary_fwnode()")
Reported-by: Ferry Toth <[email protected]>
Signed-off-by: Andy Shevchenko <[email protected]>
---
drivers/base/core.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 41feab679fa1..78114ddac755 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -4264,6 +4264,7 @@ static inline bool fwnode_is_primary(struct fwnode_handle *fwnode)
*/
void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
{
+ struct device *parent = dev->parent;
struct fwnode_handle *fn = dev->fwnode;

if (fwnode) {
@@ -4278,7 +4279,8 @@ void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
} else {
if (fwnode_is_primary(fn)) {
dev->fwnode = fn->secondary;
- fn->secondary = ERR_PTR(-ENODEV);
+ if (!(parent && fn == parent->fwnode))
+ fn->secondary = ERR_PTR(-ENODEV);
} else {
dev->fwnode = NULL;
}
--
2.28.0

2020-10-23 18:13:27

by Heikki Krogerus

Subject: Re: [PATCH v1 2/2] device property: Don't clear secondary pointer for shared primary firmware node

On Thu, Oct 22, 2020 at 09:41:00PM +0300, Andy Shevchenko wrote:
> It appears that firmware nodes can be shared between devices. In such case
> when a (child) device is about to be deleted, its firmware node may be shared
> and ACPI_COMPANION_SET(..., NULL) call for it breaks the secondary link
> of the shared primary firmware node.
>
> In order to prevent that, check, if the device has a parent and parent's
> firmware node is shared with its child, and avoid crashing the link.
>
> Fixes: c15e1bdda436 ("device property: Fix the secondary firmware node handling in set_primary_fwnode()")
> Reported-by: Ferry Toth <[email protected]>
> Signed-off-by: Andy Shevchenko <[email protected]>

FWIW:

Reviewed-by: Heikki Krogerus <[email protected]>

> ---
> drivers/base/core.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/base/core.c b/drivers/base/core.c
> index 41feab679fa1..78114ddac755 100644
> --- a/drivers/base/core.c
> +++ b/drivers/base/core.c
> @@ -4264,6 +4264,7 @@ static inline bool fwnode_is_primary(struct fwnode_handle *fwnode)
> */
> void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
> {
> + struct device *parent = dev->parent;
> struct fwnode_handle *fn = dev->fwnode;
>
> if (fwnode) {
> @@ -4278,7 +4279,8 @@ void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
> } else {
> if (fwnode_is_primary(fn)) {
> dev->fwnode = fn->secondary;
> - fn->secondary = ERR_PTR(-ENODEV);
> + if (!(parent && fn == parent->fwnode))
> + fn->secondary = ERR_PTR(-ENODEV);
> } else {
> dev->fwnode = NULL;
> }
> --
> 2.28.0

--
heikki

2020-10-23 18:17:29

by Ferry Toth

Subject: Re: [PATCH v1 2/2] device property: Don't clear secondary pointer for shared primary firmware node

Hi

Op 23-10-2020 om 14:35 schreef Heikki Krogerus:
> On Thu, Oct 22, 2020 at 09:41:00PM +0300, Andy Shevchenko wrote:
>> It appears that firmware nodes can be shared between devices. In such case
>> when a (child) device is about to be deleted, its firmware node may be shared
>> and ACPI_COMPANION_SET(..., NULL) call for it breaks the secondary link
>> of the shared primary firmware node.
>>
>> In order to prevent that, check, if the device has a parent and parent's
>> firmware node is shared with its child, and avoid crashing the link.
>>
>> Fixes: c15e1bdda436 ("device property: Fix the secondary firmware node handling in set_primary_fwnode()")
>> Reported-by: Ferry Toth <[email protected]>
>> Signed-off-by: Andy Shevchenko <[email protected]>
> FWIW:
>
> Reviewed-by: Heikki Krogerus <[email protected]>

Tested-by: Ferry Toth <[email protected]>

>> ---
>> drivers/base/core.c | 4 +++-
>> 1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/base/core.c b/drivers/base/core.c
>> index 41feab679fa1..78114ddac755 100644
>> --- a/drivers/base/core.c
>> +++ b/drivers/base/core.c
>> @@ -4264,6 +4264,7 @@ static inline bool fwnode_is_primary(struct fwnode_handle *fwnode)
>> */
>> void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
>> {
>> + struct device *parent = dev->parent;
>> struct fwnode_handle *fn = dev->fwnode;
>>
>> if (fwnode) {
>> @@ -4278,7 +4279,8 @@ void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
>> } else {
>> if (fwnode_is_primary(fn)) {
>> dev->fwnode = fn->secondary;
>> - fn->secondary = ERR_PTR(-ENODEV);
>> + if (!(parent && fn == parent->fwnode))
>> + fn->secondary = ERR_PTR(-ENODEV);
>> } else {
>> dev->fwnode = NULL;
>> }
>> --
>> 2.28.0

2020-10-23 18:36:01

by Ferry Toth

Subject: Re: [PATCH v1 2/2] device property: Don't clear secondary pointer for shared primary firmware node

Hi

Op 23-10-2020 om 14:35 schreef Heikki Krogerus:
> On Thu, Oct 22, 2020 at 09:41:00PM +0300, Andy Shevchenko wrote:
>> It appears that firmware nodes can be shared between devices. In such
>> case
>> when a (child) device is about to be deleted, its firmware node may
>> be shared
>> and ACPI_COMPANION_SET(..., NULL) call for it breaks the secondary link
>> of the shared primary firmware node.
>>
>> In order to prevent that, check, if the device has a parent and parent's
>> firmware node is shared with its child, and avoid crashing the link.
>>
>> Fixes: c15e1bdda436 ("device property: Fix the secondary firmware
>> node handling in set_primary_fwnode()")
>> Reported-by: Ferry Toth <[email protected]>
>> Signed-off-by: Andy Shevchenko <[email protected]>
> FWIW:
>
> Reviewed-by: Heikki Krogerus <[email protected]>

Tested-by: Ferry Toth <[email protected]>

>> ---
>> drivers/base/core.c | 4 +++-
>> 1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/base/core.c b/drivers/base/core.c
>> index 41feab679fa1..78114ddac755 100644
>> --- a/drivers/base/core.c
>> +++ b/drivers/base/core.c
>> @@ -4264,6 +4264,7 @@ static inline bool fwnode_is_primary(struct
>> fwnode_handle *fwnode)
>> */
>> void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
>> {
>> + struct device *parent = dev->parent;
>> struct fwnode_handle *fn = dev->fwnode;
>> if (fwnode) {
>> @@ -4278,7 +4279,8 @@ void set_primary_fwnode(struct device *dev,
>> struct fwnode_handle *fwnode)
>> } else {
>> if (fwnode_is_primary(fn)) {
>> dev->fwnode = fn->secondary;
>> - fn->secondary = ERR_PTR(-ENODEV);
>> + if (!(parent && fn == parent->fwnode))
>> + fn->secondary = ERR_PTR(-ENODEV);
>> } else {
>> dev->fwnode = NULL;
>> }
>> -- 2.28.0