Commit ce63c44b authored by Liang He's avatar Liang He Committed by Michael Ellerman
Browse files

powerpc/pci-common: Fix refcount bug for 'phb->dn' 



In pcibios_alloc_controller(), 'phb' is allocated and escaped into
global 'hose_list'. So we should call of_node_get() when a new reference
created into 'phb->dn'. And when phb is freed, we should call
of_node_put() on it.

NOTE: This function is called in the iteration of for_each_xx in
chrp_find_bridges() and pSeries_discover_phbs(). If there is no
of_node_get(), the object may be prematurely freed.

Signed-off-by: default avatarLiang He <windhl@126.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220702022936.266146-1-windhl@126.com
parent 605c27f3

arch/powerpc/kernel/pci-common.c

+2 −2
Original line number Diff line number Diff line
@@ -135,7 +135,7 @@ struct pci_controller *pcibios_alloc_controller(struct device_node *dev) 
	list_add_tail(&phb->list_node, &hose_list);

	spin_unlock(&hose_spinlock);



	phb->dn = dev;

	phb->dn = of_node_get(dev);

	phb->is_dynamic = slab_is_available();

#ifdef CONFIG_PPC64

	if (dev) {
@@ -158,7 +158,7 @@ void pcibios_free_controller(struct pci_controller *phb) 
	/* Clear bit of phb_bitmap to allow reuse of this PHB number. */

	if (phb->global_number < MAX_PHBS)

		clear_bit(phb->global_number, phb_bitmap);



	of_node_put(phb->dn);

	list_del(&phb->list_node);

	spin_unlock(&hose_spinlock);