linux-kernel - Re: Wake-up from suspend to RAM broken under `retbleed=stuff`

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Message-ID: <Y7qp80cK+r247eCU@zn.tnic>
Date:   Sun, 8 Jan 2023 12:33:07 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Joan Bruguera <joanbrugueram@...il.com>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        linux-kernel@...r.kernel.org, x86@...nel.org,
        Thomas Gleixner <tglx@...utronix.de>
Subject: Re: Wake-up from suspend to RAM broken under `retbleed=stuff`

On Sun, Jan 08, 2023 at 03:07:48AM +0000, Joan Bruguera wrote:
> Wake-up from suspend to RAM seems broken under `retbleed=stuff`
> (the recently introduced call depth tracking mitigation, see:
> https://lore.kernel.org/lkml/f9fd86acac4f49bc8f90b403978e9df3@AcuMS.aculab.com/t/)
> I can replicate it on both real hardware and QEMU (with and without KVM).
> 
> It can replicate it by booting a fairly standard mainline kernel

Which version exactly?

> on QEMU with `init=/bin/bash` and then suspending to RAM with:
>     echo "deep" > /sys/power/mem_sleep
>     echo "mem" > /sys/power/state
> Then executing `system_wakeup` on the QEMU monitor causes the crash.

You probably need to share .config too because my tailored .config built with
latest tip/master works fine here.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette