[PATCH 0/4] Make cpumask_of_node() robust against NUMA_NO_NODE

[John Garry]

This series aims to remedy an issue that not all per-arch versions of
cpumask_of_node() are robust against NUMA_NO_NODE.

In my view, cpumask_of_node() should be able to handle NUMA_NO_NODE. This
is because NUMA_NO_NODE is a valid index from the following flow, where
the device NUMA node is not set (from default):

device_initialize(dev)
	set_dev_node(dev, NUMA_NO_NODE);

mask = cpumask_of_node(dev_to_node(dev));

The CONFIG_DEBUG_PER_CPU_MAPS=n x86 version cpumask_of_node() would
produce an array out-of-index issue (when passed NUMA_NO_NODE), which I
think is attempted to be worked around here:
https://lore.kernel.org/linux-scsi/cf0f9085-6c87-4dd5-9114-925723e68495@xxxxxxxxxx/T/#mdedb68052e419b4bfca9ce45bb33b58988018945

I also see a CVE which also looks related:
https://nvd.nist.gov/vuln/detail/cve-2024-39277

Each per-arch version could be picked up separately, as can the
asm-generic change.

John Garry (4):
  include/asm-generic/topology.h: Remove unused definition of
    cpumask_of_node()
  LoongArch: Make cpumask_of_node() robust against NUMA_NO_NODE
  MIPS: Loongson: Make cpumask_of_node() robust against NUMA_NO_NODE
  x86/cpu/topology: Make cpumask_of_node() robust against NUMA_NO_NODE

 arch/loongarch/include/asm/topology.h            | 4 +++-
 arch/mips/include/asm/mach-loongson64/topology.h | 4 +++-
 arch/x86/include/asm/topology.h                  | 2 ++
 arch/x86/mm/numa.c                               | 2 ++
 include/asm-generic/topology.h                   | 8 ++------
 5 files changed, 12 insertions(+), 8 deletions(-)

-- 
2.43.5