Commit fc1b2531 authored Jan 23, 2014 by Andreas Noever Committed by Bjorn Helgaas Feb 11, 2014

PCI: Don't scan random busses in pci_scan_bridge()



When assigning a new bus number in pci_scan_bridge we check whether
max+1 is free by calling pci_find_bus. If it does already exist then we
assume that we are rescanning and that this is the right bus to scan.

This is fragile. If max+1 lies outside of bus->busn_res.end then we will
rescan some random bus from somewhere else in the hierachy. This patch
checks for this case and prints a warning.

[bhelgaas: add parent/child bus number info to dev_warn()]
Signed-off-by: Andreas Noever <andreas.noever@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

parent c95b0bd6

drivers/pci/probe.c

+7 −3

Original line number	Diff line number	Diff line
		@@ -829,12 +829,16 @@ int pci_scan_bridge(struct pci_bus bus, struct pci_dev dev, int max, int pass)
		goto out;
		}

		if (max >= bus->busn_res.end) {
		dev_warn(&dev->dev, "can't allocate child bus %02x from %pR\n",
		max, &bus->busn_res);
		goto out;
		}

		/* Clear errors */
		pci_write_config_word(dev, PCI_STATUS, 0xffff);

		/* Prevent assigning a bus number that already exists.
		* This can happen when a bridge is hot-plugged, so in
		* this case we only re-scan this bus. */
		/* The bus will already exist if we are rescanning */
		child = pci_find_bus(pci_domain_nr(bus), max+1);
		if (!child) {
		child = pci_add_new_bus(bus, dev, max+1);