kasprintf() returns a pointer to dynamically allocated memory
which can be NULL upon failure. Ensure the allocation was successful
by checking the pointer validity.
Signed-off-by: Kunwu Chan <[email protected]>
---
drivers/vfio/pci/vfio_pci_core.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
index 1cbc990d42e0..74e5b89a3a0c 100644
--- a/drivers/vfio/pci/vfio_pci_core.c
+++ b/drivers/vfio/pci/vfio_pci_core.c
@@ -2047,6 +2047,8 @@ static int vfio_pci_bus_notifier(struct notifier_block *nb,
pci_name(pdev));
pdev->driver_override = kasprintf(GFP_KERNEL, "%s",
vdev->vdev.ops->name);
+ if (!pdev->driver_override)
+ return -ENOMEM;
} else if (action == BUS_NOTIFY_BOUND_DRIVER &&
pdev->is_virtfn && physfn == vdev->pdev) {
struct pci_driver *drv = pci_dev_driver(pdev);
--
2.39.2
On Fri, 12 Jan 2024 14:22:21 +0800
Kunwu Chan <[email protected]> wrote:
> kasprintf() returns a pointer to dynamically allocated memory
> which can be NULL upon failure. Ensure the allocation was successful
> by checking the pointer validity.
>
> Signed-off-by: Kunwu Chan <[email protected]>
> ---
> drivers/vfio/pci/vfio_pci_core.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
> index 1cbc990d42e0..74e5b89a3a0c 100644
> --- a/drivers/vfio/pci/vfio_pci_core.c
> +++ b/drivers/vfio/pci/vfio_pci_core.c
> @@ -2047,6 +2047,8 @@ static int vfio_pci_bus_notifier(struct notifier_block *nb,
> pci_name(pdev));
> pdev->driver_override = kasprintf(GFP_KERNEL, "%s",
> vdev->vdev.ops->name);
> + if (!pdev->driver_override)
> + return -ENOMEM;
> } else if (action == BUS_NOTIFY_BOUND_DRIVER &&
> pdev->is_virtfn && physfn == vdev->pdev) {
> struct pci_driver *drv = pci_dev_driver(pdev);
This is a blocking notifier callback, so errno isn't a proper return
value, nor does it accomplish anything. We're into the realm of
worrying about small allocation failures here, which I understand
essentially cannot happen, but about the best we could do at this
point would be to WARN_ON if we weren't able to allocate an override.
Thanks,
Alex
On 2024/1/12 23:30, Alex Williamson wrote:
> On Fri, 12 Jan 2024 14:22:21 +0800
> Kunwu Chan <[email protected]> wrote:
>
>> kasprintf() returns a pointer to dynamically allocated memory
>> which can be NULL upon failure. Ensure the allocation was successful
>> by checking the pointer validity.
>>
>> Signed-off-by: Kunwu Chan <[email protected]>
>> ---
>> drivers/vfio/pci/vfio_pci_core.c | 2 ++
>> 1 file changed, 2 insertions(+)
>>
>> diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
>> index 1cbc990d42e0..74e5b89a3a0c 100644
>> --- a/drivers/vfio/pci/vfio_pci_core.c
>> +++ b/drivers/vfio/pci/vfio_pci_core.c
>> @@ -2047,6 +2047,8 @@ static int vfio_pci_bus_notifier(struct notifier_block *nb,
>> pci_name(pdev));
>> pdev->driver_override = kasprintf(GFP_KERNEL, "%s",
>> vdev->vdev.ops->name);
>> + if (!pdev->driver_override)
>> + return -ENOMEM;
>> } else if (action == BUS_NOTIFY_BOUND_DRIVER &&
>> pdev->is_virtfn && physfn == vdev->pdev) {
>> struct pci_driver *drv = pci_dev_driver(pdev);
>
> This is a blocking notifier callback, so errno isn't a proper return
> value, nor does it accomplish anything. We're into the realm of
> worrying about small allocation failures here, which I understand
> essentially cannot happen, but about the best we could do at this
> point would be to WARN_ON if we weren't able to allocate an override.
Thanks for your reply.
I'll update v2 patch use WARN_ON to print some callstack msgs when we
weren't able to allocate an override.
These msgs could reduce some of the worries and help us to find what happed.
> Thanks,
>
> Alex
>
--
Thanks,
Kunwu