Re: [6.12.y regression] Regression with 58130e7ce6cb ("PCI/ERR: Ensure error recoverability at all times"): echo vfio-pci >driver_override does not work for DVB Adapter

[Lukas Wunner <lukas@wunner.de>]

On Sat, Mar 28, 2026 at 02:37:50PM +0100, Salvatore Bonaccorso wrote:
> Bernd Schumacher reported in Debian (report and report from bisection
> in https://bugs.debian.org/1131025) a 6.12.y specific regression of
> 58130e7ce6cb ("PCI/ERR: Ensure error recoverability at all times"):

Thanks for the report and sorry for the breakage.

According to the Debian bug report, the issue only occurs on
v6.12-stable.  It does not affect v6.18 and v6.19.

I note that v6.12-stable commit 58130e7ce6cb differs from upstream
commit a2f1e22390ac in that the call to pci_save_state() is at the
top of pci_bus_add_device(), not in the middle of the function after
pci_bridge_d3_update().

@Bernd, could you test whether moving the call to pci_save_state()
as in the small patch below resolves the issue on v6.12-stable?

If it does, then the upstream commit was backported to v6.12 in an
incorrect manner.  If it does not, I need to dig deeper.

Thanks!

Lukas

-- >8 --

diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c
index 429c0c8ce93d..bdb3e10f947a 100644
--- a/drivers/pci/bus.c
+++ b/drivers/pci/bus.c
@@ -331,9 +331,6 @@ void pci_bus_add_device(struct pci_dev *dev)
 	struct device_node *dn = dev->dev.of_node;
 	int retval;
 
-	/* Save config space for error recoverability */
-	pci_save_state(dev);
-
 	/*
 	 * Can not put in pci_device_add yet because resources
 	 * are not assigned yet for some devices.
@@ -346,6 +343,9 @@ void pci_bus_add_device(struct pci_dev *dev)
 	pci_proc_attach_device(dev);
 	pci_bridge_d3_update(dev);
 
+	/* Save config space for error recoverability */
+	pci_save_state(dev);
+
 	dev->match_driver = !dn || of_device_is_available(dn);
 	retval = device_attach(&dev->dev);
 	if (retval < 0 && retval != -EPROBE_DEFER)