diff --git a/Documentation/PCI/msi-howto.rst b/Documentation/PCI/msi-howto.rst index 667ebe2156b4..844c1d3c395d 100644 --- a/Documentation/PCI/msi-howto.rst +++ b/Documentation/PCI/msi-howto.rst @@ -113,8 +113,11 @@ vectors, use the following function:: int pci_irq_vector(struct pci_dev *dev, unsigned int nr); -Any allocated resources should be freed before removing the device using -the following function:: +If the driver enables the device using pcim_enable_device(), the driver +shouldn't call pci_free_irq_vectors() because pcim_enable_device() +activates automatic management for IRQ vectors. Otherwise, the driver should +free any allocated IRQ vectors before removing the device using the following +function:: void pci_free_irq_vectors(struct pci_dev *dev); diff --git a/drivers/pci/msi/api.c b/drivers/pci/msi/api.c index 818d55fbad0d..c18559b6272c 100644 --- a/drivers/pci/msi/api.c +++ b/drivers/pci/msi/api.c @@ -370,6 +370,11 @@ EXPORT_SYMBOL(pci_irq_get_affinity); * Undo the interrupt vector allocations and possible device MSI/MSI-X * enablement earlier done through pci_alloc_irq_vectors_affinity() or * pci_alloc_irq_vectors(). + * + * WARNING: Do not call this function if the device has been enabled + * with pcim_enable_device(). In that case, IRQ vectors are automatically + * managed via pcim_msi_release() and calling pci_free_irq_vectors() can + * lead to double-free issues. */ void pci_free_irq_vectors(struct pci_dev *dev) {