PCI: Make pci_scan_slot more robust (4fb88c1a) · Commits · 戴 / test

Yinghai pointed out that the new pci_scan_slot() crashes when called on an ARI-capable slot that is empty. Fix this by exiting early from pci_scan_slot if there is no device in the slot. Also make next_ari_func() robust against devices not existing in case the ARI capability is corrupt. ARI also requires that the devices be listed in order, so if we find a function listed that is out of order, stop scanning to prevent loops. Signed-off-by:

Matthew Wilcox <matthew@wil.cx> Signed-off-by:

Jesse Barnes <jbarnes@virtuousgeek.org>

drivers/pci/probe.c

+14 −4

Original line number	Diff line number	Diff line
		@@ -1222,11 +1222,19 @@ EXPORT_SYMBOL(pci_scan_single_device);
		static unsigned next_ari_fn(struct pci_dev *dev, unsigned fn)
		{
		u16 cap;
		unsigned pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ARI);
		unsigned pos, next_fn;

		if (!dev)
		return 0;

		pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ARI);
		if (!pos)
		return 0;
		pci_read_config_word(dev, pos + 4, &cap);
		return cap >> 8;
		next_fn = cap >> 8;
		if (next_fn <= fn)
		return 0;
		return next_fn;
		}

		static unsigned next_trad_fn(struct pci_dev *dev, unsigned fn)
		@@ -1271,12 +1279,14 @@ int pci_scan_slot(struct pci_bus *bus, int devfn)
		return 0; /* Already scanned the entire slot */

		dev = pci_scan_single_device(bus, devfn);
		if (dev && !dev->is_added) /* new device? */
		if (!dev)
		return 0;
		if (!dev->is_added)
		nr++;

		if (pci_ari_enabled(bus))
		next_fn = next_ari_fn;
		else if (dev && dev->multifunction)
		else if (dev->multifunction)
		next_fn = next_trad_fn;

		for (fn = next_fn(dev, 0); fn > 0; fn = next_fn(dev, fn)) {

Admin message