Re: Kernel 6.5-rc2: system crash on suspend bisected

From: Bjorn Helgaas
Date: Thu Jul 20 2023 - 16:21:36 EST


[+cc regressions list]

On Wed, Jul 19, 2023 at 11:36:51PM -0400, Woody Suwalski wrote:
> 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.

Thank you very much for all your work debugging, bisecting, and
reporting this! This is incredibly helpful.

Original report, including complete dmesg logs for both v6.4 and
v6.5-rc2:
https://lore.kernel.org/r/11fc981c-af49-ce64-6b43-3e282728bd1a@xxxxxxxxx

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.

Bjorn