Re: [PATCH 6.4 172/292] PCI: acpiphp: Reassign resources on bridge if necessary

On Sun, Jul 23, 2023 at 11:25:29AM +0200, Linux regression tracking (Thorsten Leemhuis) wrote:

On 23.07.23 11:17, Thorsten Leemhuis wrote:

...

On 21.07.23 18:04, Greg Kroah-Hartman wrote:

...

From: Igor Mammedov imammedo@redhat.com

commit 40613da52b13fb21c5566f10b287e0ca8c12c4e9 upstream.

When using ACPI PCI hotplug, hotplugging a device with large BARs may fail if bridge windows programmed by firmware are not large enough.

[...]

Greg, just so you know, that patch (which is also queued for 6.1 and 5.15) is known to cause a regression in 6.5-rc. To quote https://lore.kernel.org/all/11fc981c-af49-ce64-6b43-3e282728bd1a@gmail.com/

Laptop shows a kernel crash trace after a first suspend to ram, on a
second attempt to suspend it becomes frozen solid. This is 100%
repeatable with a 6.5-rc2 kernel, not happening with a 6.4 kernel - see
the attached dmesg output.

I have bisected the kernel uilds and it points to :
[40613da52b13fb21c5566f10b287e0ca8c12c4e9] PCI: acpiphp: Reassign
resources on bridge if necessary

Reversing this patch seems to fix the kernel crash problem on my laptop.

Forgot to mention the reply from Bjorn:

I queued up a revert of 40613da52b13 ("PCI: acpiphp: Reassign
resources on bridge if necessary") (on my for-linus branch for v6.5).

It looks like a NULL pointer dereference; hopefully the fix is obvious
and I can drop the revert and replace it with the fix.

Thanks, I've dropped this from the stable queues now.

greg k-h