6.9-stable review patch. If anyone has any objections, please let me know.
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From: Jan Beulich jbeulich@suse.com
commit e0eec24e2e199873f43df99ec39773ad3af2bff7 upstream.
On an (old) x86 system with SRAT just covering space above 4Gb:
ACPI: SRAT: Node 0 PXM 0 [mem 0x100000000-0xfffffffff] hotplug
the commit referenced below leads to this NUMA configuration no longer being refused by a CONFIG_NUMA=y kernel (previously
NUMA: nodes only cover 6144MB of your 8185MB e820 RAM. Not used. No NUMA configuration found Faking a node at [mem 0x0000000000000000-0x000000027fffffff]
was seen in the log directly after the message quoted above), because of memblock_validate_numa_coverage() checking for NUMA_NO_NODE (only). This in turn led to memblock_alloc_range_nid()'s warning about MAX_NUMNODES triggering, followed by a NULL deref in memmap_init() when trying to access node 64's (NODE_SHIFT=6) node data.
To compensate said change, make memblock_set_node() warn on and adjust a passed in value of MAX_NUMNODES, just like various other functions already do.
Fixes: ff6c3d81f2e8 ("NUMA: optimize detection of memory with no node id assigned by firmware") Signed-off-by: Jan Beulich jbeulich@suse.com Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/1c8a058c-5365-4f27-a9f1-3aeb7fb3e7b2@suse.com Signed-off-by: Mike Rapoport (IBM) rppt@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- mm/memblock.c | 4 ++++ 1 file changed, 4 insertions(+)
--- a/mm/memblock.c +++ b/mm/memblock.c @@ -1339,6 +1339,10 @@ int __init_memblock memblock_set_node(ph int start_rgn, end_rgn; int i, ret;
+ if (WARN_ONCE(nid == MAX_NUMNODES, + "Usage of MAX_NUMNODES is deprecated. Use NUMA_NO_NODE instead\n")) + nid = NUMA_NO_NODE; + ret = memblock_isolate_range(type, base, size, &start_rgn, &end_rgn); if (ret) return ret;