On Fri, Jun 14, 2019 at 3:40 PM Young Xiao <92siuyang@xxxxxxxxx> wrote:
>
> There is otherwise a risk of a null pointer dereference.
Had you analyze the code?
How come that prevnode can become NULL?
> Signed-off-by: Young Xiao <92siuyang@xxxxxxxxx>
> ---
> drivers/pci/hotplug/cpqphp_ctrl.c | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/pci/hotplug/cpqphp_ctrl.c b/drivers/pci/hotplug/cpqphp_ctrl.c
> index b7f4e1f..3c8399f 100644
> --- a/drivers/pci/hotplug/cpqphp_ctrl.c
> +++ b/drivers/pci/hotplug/cpqphp_ctrl.c
> @@ -598,10 +598,11 @@ static struct pci_resource *get_io_resource(struct pci_resource **head, u32 size
> *head = node->next;
> } else {
> prevnode = *head;
> - while (prevnode->next != node)
> + while (prevnode && prevnode->next != node)
> prevnode = prevnode->next;
>
> - prevnode->next = node->next;
> + if (prevnode)
> + prevnode->next = node->next;
> }
> node->next = NULL;
> break;
> @@ -788,10 +789,11 @@ static struct pci_resource *get_resource(struct pci_resource **head, u32 size)
> *head = node->next;
> } else {
> prevnode = *head;
> - while (prevnode->next != node)
> + while (prevnode && prevnode->next != node)
> prevnode = prevnode->next;
>
> - prevnode->next = node->next;
> + if (prevnode)
> + prevnode->next = node->next;
> }
> node->next = NULL;
> break;
> --
> 2.7.4
>
--
With Best Regards,
Andy Shevchenko
