From 437aa64c8e32b724fc6d60100ef0eb313d32c88f Mon Sep 17 00:00:00 2001 From: =?utf8?q?Ilpo=20J=C3=A4rvinen?= Date: Mon, 27 Oct 2025 15:24:23 +0200 Subject: [PATCH] PCI: Do not size non-existing prefetchable window MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit pbus_size_mem() should only be called for bridge windows that exist but __pci_bus_size_bridges() may point 'pref' to a resource that does not exist (has zero flags) in case of non-root buses. When prefetchable bridge window does not exist, the same non-prefetchable bridge window is sized more than once which may result in duplicating entries into the realloc_head list. Duplicated entries are shown in this log and trigger a WARN_ON() because realloc_head had residual entries after the resource assignment algorithm: pci 0000:00:03.0: [11ab:6820] type 01 class 0x060400 PCIe Root Port pci 0000:00:03.0: PCI bridge to [bus 00] pci 0000:00:03.0: bridge window [io 0x0000-0x0fff] pci 0000:00:03.0: bridge window [mem 0x00000000-0x000fffff] pci 0000:00:03.0: bridge window [mem 0x00200000-0x003fffff] to [bus 02] add_size 200000 add_align 200000 pci 0000:00:03.0: bridge window [mem 0x00200000-0x003fffff] to [bus 02] add_size 200000 add_align 200000 pci 0000:00:03.0: bridge window [mem 0xe0000000-0xe03fffff]: assigned pci 0000:00:03.0: PCI bridge to [bus 02] pci 0000:00:03.0: bridge window [mem 0xe0000000-0xe03fffff] ------------[ cut here ]------------ WARNING: CPU: 0 PID: 1 at drivers/pci/setup-bus.c:2373 pci_assign_unassigned_root_bus_resources+0x1bc/0x234 Check resource flags of 'pref' and only size the prefetchable window if the resource has the IORESOURCE_PREFETCH flag. Fixes: ae88d0b9c57f ("PCI: Use pbus_select_window_for_type() during mem window sizing") Reported-by: Klaus Kudielka Closes: https://lore.kernel.org/r/51e8cf1c62b8318882257d6b5a9de7fdaaecc343.camel@gmail.com/ Signed-off-by: Ilpo Järvinen Signed-off-by: Bjorn Helgaas Tested-by: Klaus Kudielka Link: https://patch.msgid.link/20251027132423.8841-1-ilpo.jarvinen@linux.intel.com --- drivers/pci/setup-bus.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c index 4a8735b275e4..3645f392a9fd 100644 --- a/drivers/pci/setup-bus.c +++ b/drivers/pci/setup-bus.c @@ -1604,7 +1604,7 @@ void __pci_bus_size_bridges(struct pci_bus *bus, struct list_head *realloc_head) pbus_size_io(bus, realloc_head ? 0 : additional_io_size, additional_io_size, realloc_head); - if (pref) { + if (pref && (pref->flags & IORESOURCE_PREFETCH)) { pbus_size_mem(bus, IORESOURCE_MEM | IORESOURCE_PREFETCH | (pref->flags & IORESOURCE_MEM_64), -- 2.47.3