From: Mario Limonciello <mario.limonciello@amd.com>
To: x86@kernel.org, David Woodhouse <dwmw@amazon.co.uk>
Cc: LKML <linux-kernel@vger.kernel.org>,
"Gong, Richard" <Richard.Gong@amd.com>,
Thomas Gleixner <tglx@linutronix.de>,
Linux kernel regressions list <regressions@lists.linux.dev>,
Michael Kelley <mikelley@microsoft.com>,
Oleksandr Natalenko <oleksandr@natalenko.name>,
Helge Deller <deller@gmx.de>,
"Guilherme G. Piccoli" <gpiccoli@igalia.com>
Subject: Re: X86 parallel bring up regression
Date: Mon, 23 Oct 2023 11:04:31 -0500 [thread overview]
Message-ID: <450e06f8-5655-406e-b485-c19862bba6d8@amd.com> (raw)
In-Reply-To: <3d96c70e-da3b-49c2-a776-930a9f1b815d@amd.com>
On 10/19/2023 15:26, Mario Limonciello wrote:
> Hi,
>
> We've recently found that there was a regression from 6.5 that broke
> resume from suspend-to-ram on some AMD platforms.
>
> We bisected it and confirmed it's introduced by 0c7ffa32dbd6
> ("x86/smpboot/64: Implement arch_cpuhp_init_parallel_bringup() and
> enable it").
>
> Furthermore; we confirmed that on 6.6-rc6 adding cpuhp.parallel=0 to the
> kernel command line avoids the issue.
>
> Here are bootup kernel logs from an affected system at 7e75178 (doesn't
> reproduce) and 0c7ffa32 (does reproduce).
> https://gist.github.com/superm1/c251c0849956b8389309f03871fba091
>
> Is it possible that this is caused by the system entering S3 with x2apic
> enabled but leaving with it disabled?
>
> I notice in the resume path on a boot with cpuhp.parallel=0 that x2apic
> "explicitly" gets turned on again.
>
> <snip>
> smpboot: CPU 127 is now offline
> ACPI: PM: Low-level resume complete
> ACPI: PM: Restoring platform NVS memory
> x2apic enabled
> AMD-Vi: Virtual APIC enabled
> AMD-Vi: Virtual APIC enabled
> LVT offset 0 assigned for vector 0x400
> Enabling non-boot CPUs ...
> smpboot: Booting Node 0 Processor 1 APIC 0x2
> masked ExtINT on CPU#1
> ACPI: \_SB_.PLTF.C002: Found 2 idle states
> CPU1 is up
> smpboot: Booting Node 0 Processor 2 APIC 0x4
> </snip>
>
> I hypothesize this could be caused by .Lread_apicid finding x2apic
> disabled but then trying to read from apic_mmio_base which isn't
> initialized because x2apic was used (AFAICT apic_set_fixmap() never gets
> called in this case).
>
> Thanks,
AFAICT the issue is indeed that x2apic isn't re-enabled during s3
resume.
I've posted a series that I confirmed resolves the issue here:
https://lore.kernel.org/all/20231023160018.164054-1-mario.limonciello@amd.com/T/#t
next prev parent reply other threads:[~2023-10-23 16:04 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-19 20:26 Mario Limonciello
2023-10-20 6:59 ` Linux regression tracking #adding (Thorsten Leemhuis)
2023-10-23 16:04 ` Mario Limonciello [this message]
2023-11-01 12:15 ` Linux regression tracking #update (Thorsten Leemhuis)
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