linux-kernel - [PATCH v4 1/7] x86/numa: Fix SRAT lookup of CFMWS ranges with numa_fill

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Message-ID: <20240424154846.2152750-2-rrichter@amd.com>
Date: Wed, 24 Apr 2024 17:48:40 +0200
From: Robert Richter <rrichter@....com>
To: "Rafael J. Wysocki" <rafael@...nel.org>, Thomas Gleixner
	<tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>, Borislav Petkov
	<bp@...en8.de>, Dave Hansen <dave.hansen@...ux.intel.com>, <x86@...nel.org>,
	Andy Lutomirski <luto@...nel.org>, Peter Zijlstra <peterz@...radead.org>,
	"Dan Williams" <dan.j.williams@...el.com>, Alison Schofield
	<alison.schofield@...el.com>
CC: <linux-acpi@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<linux-cxl@...r.kernel.org>, Robert Richter <rrichter@....com>, Derick Marks
	<derick.w.marks@...el.com>, "H. Peter Anvin" <hpa@...or.com>
Subject: [PATCH v4 1/7] x86/numa: Fix SRAT lookup of CFMWS ranges with numa_fill_memblks()

For configurations that have the kconfig option NUMA_KEEP_MEMINFO
disabled, the SRAT lookup done with numa_fill_memblks() fails
returning NUMA_NO_MEMBLK (-1). 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.

numa_fill_memblks() is implemented and used in the init section only.
The option NUMA_KEEP_MEMINFO is only for the case when NUMA data will
be used outside of init. So fix the SRAT lookup by moving
numa_fill_memblks() out of the NUMA_KEEP_MEMINFO block to make it
always available in the init section.

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")

Fixes: 8f1004679987 ("ACPI/NUMA: Apply SRAT proximity domain to entire CFMWS window")
Cc: Derick Marks <derick.w.marks@...el.com>
Cc: Dan Williams <dan.j.williams@...el.com>
Cc: Alison Schofield <alison.schofield@...el.com>
Signed-off-by: Robert Richter <rrichter@....com>
---

Also note this patch is intended for stable, please tag it. The next
patch (using __weak instead) fixes the issue too, but is more
complex. So if this patch will not be used for stable it can be
dropped entirely in favour of the next.
---
 arch/x86/include/asm/sparsemem.h | 2 +-
 arch/x86/mm/numa.c               | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/sparsemem.h b/arch/x86/include/asm/sparsemem.h
index 1be13b2dfe8b..1aaa447ef24b 100644
--- a/arch/x86/include/asm/sparsemem.h
+++ b/arch/x86/include/asm/sparsemem.h
@@ -37,9 +37,9 @@ extern int phys_to_target_node(phys_addr_t start);
 #define phys_to_target_node phys_to_target_node
 extern int memory_add_physaddr_to_nid(u64 start);
 #define memory_add_physaddr_to_nid memory_add_physaddr_to_nid
+#endif
 extern int numa_fill_memblks(u64 start, u64 end);
 #define numa_fill_memblks numa_fill_memblks
-#endif
 #endif /* __ASSEMBLY__ */
 
 #endif /* _ASM_X86_SPARSEMEM_H */
diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c
index 65e9a6e391c0..ce84ba86e69e 100644
--- a/arch/x86/mm/numa.c
+++ b/arch/x86/mm/numa.c
@@ -929,6 +929,8 @@ int memory_add_physaddr_to_nid(u64 start)
 }
 EXPORT_SYMBOL_GPL(memory_add_physaddr_to_nid);
 
+#endif
+
 static int __init cmp_memblk(const void *a, const void *b)
 {
 	const struct numa_memblk *ma = *(const struct numa_memblk **)a;
@@ -1001,5 +1003,3 @@ int __init numa_fill_memblks(u64 start, u64 end)
 	}
 	return 0;
 }
-
-#endif
-- 
2.39.2