From: Ilpo Järvinen Date: Fri, 13 Mar 2026 08:45:50 +0000 (+0200) Subject: PCI: Fix premature removal from realloc_head list during resource assignment X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1ee4716a5a28eaef81ae1f280d983258bee49623;p=thirdparty%2Fkernel%2Fstable.git PCI: Fix premature removal from realloc_head list during resource assignment reassign_resources_sorted() checks for two things: a) Resource assignment failures for mandatory resources by checking if the resource remains unassigned, which are known to always repeat, and does not attempt to assign them again. b) That resource is not among the ones being processed/assigned at this stage, leading to skip processing such resources in reassign_resources_sorted() as well (resource assignment progresses one PCI hierarchy level at a time). The problem here is that a) is checked before b), but b) also implies the resource is not being assigned yet, making also a) true. As a) only skips resource assignment but still removes the resource from realloc_head, the later stages that would need to process the information in realloc_head cannot obtain the optional size information anymore. This leads to considering only non-optional part for bridge windows deeper in the PCI hierarchy. This problem has been observed during rescan (add_size is not considered while attempting assignment for 0000:e2:00.0 indicating the corresponding entry was removed from realloc_head while processing resource assignments for 0000:e1): pci_bus 0000:e1: scanning bus ... pci 0000:e3:01.0: bridge window [mem 0x800000000-0x1000ffffff 64bit pref] to [bus e4] add_size 60c000000 add_align 800000000 pci 0000:e3:01.0: bridge window [mem 0x00100000-0x000fffff] to [bus e4] add_size 200000 add_align 200000 pci 0000:e3:02.0: disabling bridge window [mem 0x00000000-0x000fffff 64bit pref] to [bus e5] (unused) pci 0000:e2:00.0: bridge window [mem 0x800000000-0x1000ffffff 64bit pref] to [bus e3-e5] add_size 60c000000 add_align 800000000 pci 0000:e2:00.0: bridge window [mem 0x00100000-0x001fffff] to [bus e3-e5] add_size 200000 add_align 200000 pcieport 0000:e1:02.0: bridge window [io size 0x2000]: can't assign; no space pcieport 0000:e1:02.0: bridge window [io size 0x2000]: failed to assign pcieport 0000:e1:02.0: bridge window [io 0x1000-0x2fff]: resource restored pcieport 0000:e1:02.0: bridge window [io 0x1000-0x2fff]: resource restored pcieport 0000:e1:02.0: bridge window [io size 0x2000]: can't assign; no space pcieport 0000:e1:02.0: bridge window [io size 0x2000]: failed to assign pci 0000:e2:00.0: bridge window [mem 0x28f000000000-0x28f800ffffff 64bit pref]: assigned Fixes: 96336ec70264 ("PCI: Perform reset_resource() and build fail list in sync") Reported-by: Peter Nisbet Signed-off-by: Ilpo Järvinen Signed-off-by: Bjorn Helgaas Tested-by: Peter Nisbet Link: https://patch.msgid.link/20260313084551.1934-1-ilpo.jarvinen@linux.intel.com --- diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c index 1f87b018799f..9506845c112c 100644 --- a/drivers/pci/setup-bus.c +++ b/drivers/pci/setup-bus.c @@ -434,6 +434,10 @@ static void reassign_resources_sorted(struct list_head *realloc_head, dev = add_res->dev; idx = pci_resource_num(dev, res); + /* Skip this resource if not found in head list */ + if (!res_to_dev_res(head, res)) + continue; + /* * Skip resource that failed the earlier assignment and is * not optional as it would just fail again. @@ -442,10 +446,6 @@ static void reassign_resources_sorted(struct list_head *realloc_head, !pci_resource_is_optional(dev, idx)) goto out; - /* Skip this resource if not found in head list */ - if (!res_to_dev_res(head, res)) - continue; - res_name = pci_resource_name(dev, idx); add_size = add_res->add_size; align = add_res->min_align;