Commit a34d7487 authored by Ilpo Järvinen's avatar Ilpo Järvinen Committed by Bjorn Helgaas
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PCI: Restore assigned resources fully after release 



PCI resource fitting code in __assign_resources_sorted() runs in multiple
steps. A resource that was successfully assigned may have to be released
before the next step attempts assignment again. The assign+release cycle is
destructive to a start-aligned struct resource (bridge window or IOV
resource) because the start field is overwritten with the real address when
the resource got assigned.

One symptom:

  pci 0002:00:00.0: bridge window [mem size 0x00100000]: can't assign; bogus alignment

Properly restore the resource after releasing it. The start, end, and flags
fields must be stored into the related struct pci_dev_resource in order to
be able to restore the resource to its original state.

Fixes: 96336ec7 ("PCI: Perform reset_resource() and build fail list in sync")
Reported-by: default avatarGuenter Roeck <linux@roeck-us.net>
Closes: https://lore.kernel.org/r/01eb7d40-f5b5-4ec5-b390-a5c042c30aff@roeck-us.net/


Reported-by: default avatarNicolas Frattaroli <nicolas.frattaroli@collabora.com>
Closes: https://lore.kernel.org/r/3578030.5fSG56mABF@workhorse


Signed-off-by: default avatarIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Tested-by: default avatarNicolas Frattaroli <nicolas.frattaroli@collabora.com>
Tested-by: default avatarGuenter Roeck <linux@roeck-us.net>
Tested-by: default avatarOndrej Jirman <megi@xff.cz>
Link: https://patch.msgid.link/20250403093137.1481-1-ilpo.jarvinen@linux.intel.com
parent 0af2f6be

drivers/pci/setup-bus.c

+4 −0
Original line number Diff line number Diff line
@@ -187,6 +187,9 @@ static void pdev_sort_resources(struct pci_dev *dev, struct list_head *head) 
			panic("%s: kzalloc() failed!\n", __func__);

		tmp->res = r;

		tmp->dev = dev;

		tmp->start = r->start;

		tmp->end = r->end;

		tmp->flags = r->flags;



		/* Fallback is smallest one or list is empty */

		n = head;
@@ -545,6 +548,7 @@ static void __assign_resources_sorted(struct list_head *head, 
		pci_dbg(dev, "%s %pR: releasing\n", res_name, res);



		release_resource(res);

		restore_dev_resource(dev_res);

	}

	/* Restore start/end/flags from saved list */

	list_for_each_entry(save_res, &save_head, list)