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Date: Fri, 3 May 2024 21:46:32 +0200
From: Borislav Petkov <bp@alien8.de>
To: Robert Richter <rrichter@amd.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>,
	Dave Hansen <dave.hansen@linux.intel.com>, x86@kernel.org,
	Andy Lutomirski <luto@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Alison Schofield <alison.schofield@intel.com>,
	Dan Williams <dan.j.williams@intel.com>, linux-acpi@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-cxl@vger.kernel.org,
	Derick Marks <derick.w.marks@intel.com>,
	Jonathan Cameron <Jonathan.Cameron@huawei.com>,
	"H. Peter Anvin" <hpa@zytor.com>, Len Brown <lenb@kernel.org>
Subject: Re: [PATCH v7 1/4] x86/numa: Fix SRAT lookup of CFMWS ranges with
 numa_fill_memblks()
Message-ID: <20240503194632.GBZjU_GOFUNDD-3zkK@fat_crate.local>
References: <20240502131012.2385725-1-rrichter@amd.com>
 <20240502131012.2385725-2-rrichter@amd.com>
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In-Reply-To: <20240502131012.2385725-2-rrichter@amd.com>

On Thu, May 02, 2024 at 03:10:09PM +0200, Robert Richter wrote:
> For configurations that have the kconfig option NUMA_KEEP_MEMINFO
> disabled, numa_fill_memblks() only returns with NUMA_NO_MEMBLK (-1).
> SRAT lookup fails then because an existing SRAT memory range cannot be
> found for a CFMWS address range. This causes the addition of a
> duplicate numa_memblk with a different node id and a subsequent page
> fault and kernel crash during boot.
> 
> Fix this by making numa_fill_memblks() always available regardless of
> NUMA_KEEP_MEMINFO.
> 
> As Dan suggested, the fix is implemented to remove numa_fill_memblks()
> from sparsemem.h and alos using __weak for the function.
> 
> Note that the issue was initially introduced with [1]. But since
> phys_to_target_node() was originally used that returned the valid node
> 0, an additional numa_memblk was not added. Though, the node id was
> wrong too, a message is seen then in the logs:
> 
>  kernel/numa.c:  pr_info_once("Unknown target node for memory at 0x%llx, assuming node 0\n",
> 
> [1] commit fd49f99c1809 ("ACPI: NUMA: Add a node and memblk for each
>     CFMWS not in SRAT")
> 
> Suggested-by: Dan Williams <dan.j.williams@intel.com>
> Link: https://lore.kernel.org/all/66271b0072317_69102944c@dwillia2-xfh.jf.intel.com.notmuch/
> Fixes: 8f1004679987 ("ACPI/NUMA: Apply SRAT proximity domain to entire CFMWS window")
> Cc: Derick Marks <derick.w.marks@intel.com>
> Cc: Dan Williams <dan.j.williams@intel.com>
> Cc: Alison Schofield <alison.schofield@intel.com>
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> Reviewed-by: Alison Schofield <alison.schofield@intel.com>
> Reviewed-by: Dan Williams <dan.j.williams@intel.com>
> Signed-off-by: Robert Richter <rrichter@amd.com>
> ---
>  arch/x86/include/asm/sparsemem.h | 2 --
>  arch/x86/mm/numa.c               | 4 ++--
>  drivers/acpi/numa/srat.c         | 5 +++++
>  include/linux/numa.h             | 7 +------
>  4 files changed, 8 insertions(+), 10 deletions(-)

This needs to go through the ACPI tree but because Robert asked and FWIW:

Acked-by: Borislav Petkov (AMD) <bp@alien8.de>

Thx.

-- 
Regards/Gruss,
    Boris.

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