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From: Thomas Gleixner <tglx@linutronix.de>
To: Christian Heusel <christian@heusel.eu>
Cc: Peter Schneider <pschneider1968@googlemail.com>,
	LKML <linux-kernel@vger.kernel.org>,
	x86@kernel.org, stable@vger.kernel.org,
	regressions@lists.linux.dev
Subject: Re: Kernel 6.9 regression: X86: Bogus messages from topology detection
Date: Fri, 31 May 2024 17:25:00 +0200	[thread overview]
Message-ID: <87plt26m2b.ffs@tglx> (raw)
In-Reply-To: <43c15a7b-6f43-410e-800e-2ebec87ea762@heusel.eu>

On Fri, May 31 2024 at 16:29, Christian Heusel wrote:

P-Cores are consistent:

> CPU 0:
>    0x0000000b 0x01: eax=0x00000006 ebx=0x0000000c ecx=0x00000201 edx=0x00000000

>    0x0000001f 0x00: eax=0x00000001 ebx=0x00000002 ecx=0x00000100 edx=0x00000000

E-Cores are not:

> CPU 4:
>    0x0000000b 0x01: eax=0x00000006 ebx=0x0000000c ecx=0x00000201 edx=0x00000010

>    0x0000001f 0x01: eax=0x00000007 ebx=0x0000000c ecx=0x00000201 edx=0x00000010

As the topology is evaluated from CPU0 CPUID leaf 0x1f it's obvious that
CPU4...11 will trigger the sanity checks because their CPUID leaf 0x1f
subleaf 1 entries are bogus.

IOW it's a firmware bug and there is nothing the kernel will and can do
about it except what it does already: complaining about the inconsistency.

Thanks for providing all the information!

       tglx


  reply	other threads:[~2024-05-31 15:25 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-05-27  7:29 Kernel 6.9 regression: X86: Bogus messages from topology detection Peter Schneider
2024-05-27 13:14 ` Thomas Gleixner
2024-05-27 20:49   ` Thomas Gleixner
2024-05-27 21:06   ` Peter Schneider
2024-05-27 21:15     ` Peter Schneider
2024-05-27 21:34       ` Christian Heusel
2024-05-30  8:30       ` Thomas Gleixner
2024-05-30 10:06         ` Peter Schneider
2024-05-30 13:35           ` Thomas Gleixner
2024-05-30 15:53             ` Thomas Gleixner
2024-05-30 16:24               ` Thomas Gleixner
2024-05-31  6:52                 ` Peter Schneider
2024-05-31  8:33                   ` Thomas Gleixner
2024-05-31  8:42                     ` Thomas Gleixner
2024-05-31  9:41                       ` Peter Schneider
2024-05-31 10:07                         ` Thomas Gleixner
2024-05-31 10:22                           ` Peter Schneider
2024-06-01  7:06                       ` Linux regression tracking (Thorsten Leemhuis)
2024-06-01  7:20                         ` Thomas Gleixner
2024-06-01  7:25                           ` Linux regression tracking (Thorsten Leemhuis)
2024-05-31  8:13                 ` Christian Heusel
2024-05-31  8:16                   ` Christian Heusel
2024-05-31  8:48                     ` Thomas Gleixner
2024-05-31  9:11                       ` Thomas Gleixner
2024-05-31 13:08                         ` Christian Heusel
2024-05-31 13:42                           ` Thomas Gleixner
2024-05-31 14:29                             ` Christian Heusel
2024-05-31 15:25                               ` Thomas Gleixner [this message]
2024-05-31 11:06                     ` Thomas Gleixner

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