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From: Rik van Riel <riel@surriel.com>
To: Oleksandr Natalenko <oleksandr@natalenko.name>, x86@kernel.org
Cc: linux-kernel@vger.kernel.org, bp@alien8.de, peterz@infradead.org,
	 dave.hansen@linux.intel.com, zhengqi.arch@bytedance.com,
	nadav.amit@gmail.com, 	thomas.lendacky@amd.com,
	kernel-team@meta.com, linux-mm@kvack.org,
		akpm@linux-foundation.org, jackmanb@google.com,
	jannh@google.com, 	mhklinux@outlook.com,
	andrew.cooper3@citrix.com, Manali.Shukla@amd.com
Subject: Re: [PATCH v12 00/16] AMD broadcast TLB invalidation
Date: Sat, 22 Feb 2025 11:05:41 -0500	[thread overview]
Message-ID: <eb2feccb1874399699731aa9f16049a375b0f9a9.camel@surriel.com> (raw)
In-Reply-To: <5861243.DvuYhMxLoT@natalenko.name>

On Sat, 2025-02-22 at 12:29 +0100, Oleksandr Natalenko wrote:
> 
> [   24.381400] RIP: 0010:get_cpu_cap+0x39b/0x4f0
> 

> $ scripts/faddr2line arch/x86/kernel/cpu/common.o get_cpu_cap+0x39b
> get_cpu_cap+0x39b/0x500:
> get_cpu_cap at …/arch/x86/kernel/cpu/common.c:1063
> 
> 1060         if (c->extended_cpuid_level >= 0x80000008) {
> 1061                 cpuid(0x80000008, &eax, &ebx, &ecx, &edx);
> 1062                 c->x86_capability[CPUID_8000_0008_EBX] = ebx;
> 1063                 invlpgb_count_max = (edx & 0xffff) + 1;
> 1064         }
> ```
> 
> Any idea what I'm looking at?

It's crashing when writing the value to the
invlpgb_count_max variable.

This would be because:
1) invlpgb_count_max is marked __ro_after_init, making
   it read-only after the system has finished booting, but
2) get_cpu_cap gets run at resume and CPU hotplug time!

Borislav, do you prefer I move the initialization of 
invlpgb_count_max back to where it was before, or get
rid of the __ro_after_init thing?

-- 
All Rights Reversed.


  parent reply	other threads:[~2025-02-22 16:06 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-02-21  0:52 Rik van Riel
2025-02-21  0:53 ` [PATCH v12 01/16] x86/mm: make MMU_GATHER_RCU_TABLE_FREE unconditional Rik van Riel
2025-02-21  0:53 ` [PATCH v12 02/16] x86/mm: remove pv_ops.mmu.tlb_remove_table call Rik van Riel
2025-02-21  0:53 ` [PATCH v12 03/16] x86/mm: consolidate full flush threshold decision Rik van Riel
2025-02-21  0:53 ` [PATCH v12 04/16] x86/mm: get INVLPGB count max from CPUID Rik van Riel
2025-02-21  1:58   ` Borislav Petkov
2025-02-21  2:25     ` Rik van Riel
2025-02-21 18:03     ` [PATCH v12.1 " Rik van Riel
2025-02-21 18:41       ` Tom Lendacky
2025-02-22  3:35         ` [PATCH v12.2 " Rik van Riel
2025-02-21  0:53 ` [PATCH v12 05/16] x86/mm: add INVLPGB support code Rik van Riel
2025-02-21  0:53 ` [PATCH v12 06/16] x86/mm: use INVLPGB for kernel TLB flushes Rik van Riel
2025-02-21  0:53 ` [PATCH v12 07/16] x86/mm: use INVLPGB in flush_tlb_all Rik van Riel
2025-02-21  0:53 ` [PATCH v12 08/16] x86/mm: use broadcast TLB flushing for page reclaim TLB flushing Rik van Riel
2025-02-21  0:53 ` [PATCH v12 09/16] x86/mm: global ASID allocation helper functions Rik van Riel
2025-02-21  0:53 ` [PATCH v12 10/16] x86/mm: global ASID context switch & TLB flush handling Rik van Riel
2025-02-21  0:53 ` [PATCH v12 11/16] x86/mm: global ASID process exit helpers Rik van Riel
2025-02-21  0:53 ` [PATCH v12 12/16] x86/mm: enable broadcast TLB invalidation for multi-threaded processes Rik van Riel
2025-02-21  0:53 ` [PATCH v12 13/16] x86/mm: do targeted broadcast flushing from tlbbatch code Rik van Riel
2025-02-21  0:53 ` [PATCH v12 14/16] x86/mm: enable AMD translation cache extensions Rik van Riel
2025-02-21  0:53 ` [PATCH v12 15/16] x86/mm: only invalidate final translations with INVLPGB Rik van Riel
2025-02-21  0:53 ` [PATCH v12 16/16] x86/mm: add noinvlpgb commandline option Rik van Riel
2025-02-22 11:29 ` [PATCH v12 00/16] AMD broadcast TLB invalidation Oleksandr Natalenko
2025-02-22 11:36   ` Oleksandr Natalenko
2025-02-22 16:05   ` Rik van Riel [this message]
2025-02-22 16:19     ` Borislav Petkov

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