From 3b28cf32cc32594710590685ee478f697ed4f328 Mon Sep 17 00:00:00 2001 From: Yinghai Lu <yinghai@kernel.org> Date: Wed, 2 Mar 2011 15:14:58 -0800 Subject: [PATCH] x86, numa: Fix numa_emulation code with memory-less node0 This crash happens on a system that does not have RAM on node0. When numa_emulation is compiled in, and: 1. we boot the system without numa=fake... 2. or we boot the system with numa=fake=128 to make emulation fail we will get: [ 0.076025] ------------[ cut here ]------------ [ 0.080004] kernel BUG at arch/x86/mm/numa_64.c:788! [ 0.080004] invalid opcode: 0000 [#1] SMP [...] need to use early_cpu_to_node() directly, because cpu_to_apicid and apicid_to_node will return node0 that is not onlined. Signed-off-by: Yinghai Lu <yinghai@kernel.org> Acked-by: Tejun Heo <tj@kernel.org> Cc: David Rientjes <rientjes@google.com> LKML-Reference: <4D6ECF72.5010308@kernel.org> Signed-off-by: Ingo Molnar <mingo@elte.hu> --- arch/x86/mm/numa_64.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) diff --git a/arch/x86/mm/numa_64.c b/arch/x86/mm/numa_64.c index 95ea1551eebc..1337c51b07d7 100644 --- a/arch/x86/mm/numa_64.c +++ b/arch/x86/mm/numa_64.c @@ -780,11 +780,7 @@ void __cpuinit numa_add_cpu(int cpu) int physnid; int nid = NUMA_NO_NODE; - apicid = early_per_cpu(x86_cpu_to_apicid, cpu); - if (apicid != BAD_APICID) - nid = apicid_to_node[apicid]; - if (nid == NUMA_NO_NODE) - nid = early_cpu_to_node(cpu); + nid = early_cpu_to_node(cpu); BUG_ON(nid == NUMA_NO_NODE || !node_online(nid)); /*