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Commit 3b28cf32 authored by Yinghai Lu's avatar Yinghai Lu Committed by Ingo Molnar
Browse files

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: default avatarYinghai Lu <yinghai@kernel.org>
Acked-by: default avatarTejun Heo <tj@kernel.org>
Cc: David Rientjes <rientjes@google.com>
LKML-Reference: <4D6ECF72.5010308@kernel.org>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 6670e9cd

arch/x86/mm/numa_64.c

+1 −5
Original line number Diff line number Diff line
@@ -780,10 +780,6 @@ 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);

	BUG_ON(nid == NUMA_NO_NODE || !node_online(nid));