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authorTejun Heo <tj@kernel.org>2017-08-28 14:51:27 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-09-07 08:34:09 +0200
commit15e94ec4ec2155cae1e0de64b5ea16277c21daf8 (patch)
tree5a9ac41e3a0200facfd2056c2d7b27dd32f88525
parent857d0b3dd7566ebb70686a009c7100322ddf3bbe (diff)
downloadlinux-linaro-stable-15e94ec4ec2155cae1e0de64b5ea16277c21daf8.tar.gz
cpumask: fix spurious cpumask_of_node() on non-NUMA multi-node configs
commit b339752d054fb32863418452dff350a1086885b1 upstream. When !NUMA, cpumask_of_node(@node) equals cpu_online_mask regardless of @node. The assumption seems that if !NUMA, there shouldn't be more than one node and thus reporting cpu_online_mask regardless of @node is correct. However, that assumption was broken years ago to support DISCONTIGMEM and whether a system has multiple nodes or not is separately controlled by NEED_MULTIPLE_NODES. This means that, on a system with !NUMA && NEED_MULTIPLE_NODES, cpumask_of_node() will report cpu_online_mask for all possible nodes, indicating that the CPUs are associated with multiple nodes which is an impossible configuration. This bug has been around forever but doesn't look like it has caused any noticeable symptoms. However, it triggers a WARN recently added to workqueue to verify NUMA affinity configuration. Fix it by reporting empty cpumask on non-zero nodes if !NUMA. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-and-tested-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--include/asm-generic/topology.h6
1 files changed, 5 insertions, 1 deletions
diff --git a/include/asm-generic/topology.h b/include/asm-generic/topology.h
index fc824e2828f3..5d2add1a6c96 100644
--- a/include/asm-generic/topology.h
+++ b/include/asm-generic/topology.h
@@ -48,7 +48,11 @@
#define parent_node(node) ((void)(node),0)
#endif
#ifndef cpumask_of_node
-#define cpumask_of_node(node) ((void)node, cpu_online_mask)
+ #ifdef CONFIG_NEED_MULTIPLE_NODES
+ #define cpumask_of_node(node) ((node) == 0 ? cpu_online_mask : cpu_none_mask)
+ #else
+ #define cpumask_of_node(node) ((void)node, cpu_online_mask)
+ #endif
#endif
#ifndef pcibus_to_node
#define pcibus_to_node(bus) ((void)(bus), -1)