pdev_sort_resources() uses pdev_resources_assignable() helper to decide if device's resources cannot be assigned. pbus_size_mem(), on the other hand, does not do the same check. This could lead into a situation where a resource ends up on realloc_head list but is not on the head list, which is turn prevents emptying the resource from the realloc_head list in __assign_resources_sorted().
A non-empty realloc_head is unacceptable because it triggers an internal sanity check as show in this log with a device that has class 0 (PCI_CLASS_NOT_DEFINED):
pci 0001:01:00.0: [144d:a5a5] type 00 class 0x000000 PCIe Endpoint pci 0001:01:00.0: BAR 0 [mem 0x00000000-0x000fffff 64bit] pci 0001:01:00.0: ROM [mem 0x00000000-0x0000ffff pref] pci 0001:01:00.0: enabling Extended Tags pci 0001:01:00.0: PME# supported from D0 D3hot D3cold pci 0001:01:00.0: 15.752 Gb/s available PCIe bandwidth, limited by 8.0 GT/s PCIe x2 link at 0001:00:00.0 (capable of 31.506 Gb/s with 16.0 GT/s PCIe x2 link) pcieport 0001:00:00.0: bridge window [mem 0x00100000-0x001fffff] to [bus 01-ff] add_size 100000 add_align 100000 pcieport 0001:00:00.0: bridge window [mem 0x40000000-0x401fffff]: assigned ------------[ cut here ]------------ kernel BUG at drivers/pci/setup-bus.c:2532! Internal error: Oops - BUG: 00000000f2000800 [#1] SMP ... Call trace: pci_assign_unassigned_bus_resources+0x110/0x114 (P) pci_rescan_bus+0x28/0x48
Use pdev_resources_assignable() also within pbus_size_mem() to skip processing of non-assignable resources which removes the disparity in between what resources pdev_sort_resources() and pbus_size_mem() consider. As non-assignable resources are no longer processed, they are not added to the realloc_head list, thus the sanity check no longer triggers.
This disparity problem is very old but only now became apparent after the commit 2499f5348431 ("PCI: Rework optional resource handling") that made the ROM resources optional when calculating bridge window sizes which required adding the resource to the realloc_head list. Previously, bridge windows were just sized larger than necessary.
Fixes: 2499f5348431 ("PCI: Rework optional resource handling") Reported-by: Tudor Ambarus tudor.ambarus@linaro.org Closes: https://lore.kernel.org/all/5f103643-5e1c-43c6-b8fe-9617d3b5447c@linaro.org/ Signed-off-by: Ilpo Järvinen ilpo.jarvinen@linux.intel.com Cc: stable@vger.kernel.org --- drivers/pci/setup-bus.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c index 527f0479e983..df5aec46c29d 100644 --- a/drivers/pci/setup-bus.c +++ b/drivers/pci/setup-bus.c @@ -1191,6 +1191,7 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask, resource_size_t r_size;
if (r->parent || (r->flags & IORESOURCE_PCI_FIXED) || + !pdev_resources_assignable(dev) || ((r->flags & mask) != type && (r->flags & mask) != type2 && (r->flags & mask) != type3))