From 1e398eae8407abdc02cde8a449b14d17ed193d56 Mon Sep 17 00:00:00 2001 From: Lukas Wunner Date: Mon, 2 May 2016 13:48:25 -0500 Subject: [PATCH] PCI: Fix BUG on device attach failure 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. Fixes: ab1a187bba5c ("PCI: Check device_attach() return value always") Signed-off-by: Lukas Wunner Signed-off-by: Bjorn Helgaas Acked-by: Rafael J. Wysocki --- 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 6c9f5467bc5f..23a39fdc311e 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); -- 2.20.1