Previously when pci_bus_add_device() called device_attach() and it
returned a negative value, we emitted a WARN but carried on.
Commit ab1a187bba5c ("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.
Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Signed-off-by: Lukas Wunner <lukas@xxxxxxxxx>
---
v2: Split commit in two (Bjorn Helgaas).
drivers/pci/bus.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c
index 6c9f546..23a39fd 100644
--- a/drivers/pci/bus.c
+++ b/drivers/pci/bus.c
@@ -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);
--
2.8.0.rc3
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