Re: [PATCH v3 1/5] x86/numa: Fix SRAT lookup of CFMWS ranges with numa_fill_memblks()

[Alison Schofield]

On Fri, Apr 19, 2024 at 04:01:59PM +0200, Robert Richter wrote:
> 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.
> 
> [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@xxxxxxxxx>
> Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
> Cc: Alison Schofield <alison.schofield@xxxxxxxxx>
> Signed-off-by: Robert Richter <rrichter@xxxxxxx>
> ---

with the assumption that this is passing 0-day builds...

Reviewed-by: Alison Schofield <alison.schofield@xxxxxxxxx>


>  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
>