Re: Linux 4.15-rc2: Regression in resume from ACPI S3

From: Rafael J. Wysocki
Date: Mon Dec 04 2017 - 17:25:51 EST

On Sunday, December 3, 2017 5:22:56 PM CET Linus Torvalds wrote:
> It's Sunday, but a few hours earlier than usual, since I'm on the east
> coast, three hours ahead of my normal release schedule.
> It's a slightly bigger rc2 than I would have wished for, but this
> early in the release process I don't worry about it. The appended
> shortlog gives the details, it's fixes all over the place -
> architectures, drivers, filesystems, networking, core kernel.
> One thing I'll point out is that I'm trying to get some kernel ASLR
> leaks plugged, and as part of that we now hash any pointers printed by
> "%p' by default. That won't affect a lot of people, but where it is a
> debugging problem (rather than leaking interesting kernel pointers),
> we will have to fix things up.
> It can be a small annoyance, but the alternatives (trying to actually
> find all the cases where we might be leaking) were worse. But let's
> see if anybody even notices - a lot of the pointer printouts are stale
> debug information from when some driver was originally written, and
> aren't actually really interesting.
> There will probably be some more leak fixes during this rc process,
> we'll see how that all sorts out.

So far, resume from suspend-to-RAM (ACPI S3) is broken on all of the
systems I have tested, so it is probably safe to assume it to be
broken everywhere.

I'm quite confident that this is not something that went in through the
PM tree, because I was running those changes on the systems that turn
out to be broken now.

It looks like the the ACPI waking vector mechanism stopped working, so
I'm suspecting some x86 changes having to do with virtual-to-physical
address mapping.

I've just started bisection.