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PCI: Fix BUG on device attach failure

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Previously when pci_bus_add_device() called device_attach() and it returned
a negative value, we emitted a WARN but carried on.

Commit ab1a187bba ("PCI: Check device_attach() return value always"),
introduced in Linux 4.6-rc1, changed this to unwind all steps preceding
device_attach() and to not set dev->is_added = 1.

The latter leads to a BUG if pci_bus_add_device() was called from
pci_bus_add_devices().  Fix by not recursing to a child bus if
device_attach() failed for the bridge leading to it.

This can be triggered by plugging in a PCI device (e.g. Thunderbolt) while
the system is asleep.  The system locks up when woken because
device_attach() returns -EPROBE_DEFER.

Fixes: ab1a187bba ("PCI: Check device_attach() return value always")
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Lukas Wunner 2016-05-02 13:48:25 -05:00 committed by Bjorn Helgaas
parent 67e658794c
commit 1e398eae84
1 changed files with 3 additions and 1 deletions
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4
drivers/pci/bus.c
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@ -324,7 +324,9 @@ void pci_bus_add_devices(const struct pci_bus *bus)
}
list_for_each_entry(dev, &bus->devices, bus_list) {
BUG_ON(!dev->is_added);
/* Skip if device attach failed */
if (!dev->is_added)
continue;
child = dev->subordinate;
if (child)
pci_bus_add_devices(child);