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Subject[PATCH 4.18 091/123] s390/numa: move initial setup of node_to_cpumask_map
Date
4.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Martin Schwidefsky <schwidefsky@de.ibm.com>

commit fb7d7518b0d65955f91c7b875c36eae7694c69bd upstream.

The numa_init_early initcall sets the node_to_cpumask_map[0] to the
full cpu_possible_mask. Unfortunately this early_initcall is too late,
the NUMA setup for numa=emu is done even earlier. The order of calls
is numa_setup() -> emu_update_cpu_topology(), then the early_initcalls(),
followed by sched_init_domains().

Starting with git commit 051f3ca02e46432c0965e8948f00c07d8a2f09c0
"sched/topology: Introduce NUMA identity node sched domain"
the incorrect node_to_cpumask_map[0] really screws up the domain
setup and the kernel panics with the follow oops:

Cc: <stable@vger.kernel.org> # v4.15+
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/s390/numa/numa.c | 16 ++--------------
1 file changed, 2 insertions(+), 14 deletions(-)

--- a/arch/s390/numa/numa.c
+++ b/arch/s390/numa/numa.c
@@ -134,6 +134,8 @@ void __init numa_setup(void)
{
pr_info("NUMA mode: %s\n", mode->name);
nodes_clear(node_possible_map);
+ /* Initially attach all possible CPUs to node 0. */
+ cpumask_copy(&node_to_cpumask_map[0], cpu_possible_mask);
if (mode->setup)
mode->setup();
numa_setup_memory();
@@ -141,20 +143,6 @@ void __init numa_setup(void)
}

/*
- * numa_init_early() - Initialization initcall
- *
- * This runs when only one CPU is online and before the first
- * topology update is called for by the scheduler.
- */
-static int __init numa_init_early(void)
-{
- /* Attach all possible CPUs to node 0 for now. */
- cpumask_copy(&node_to_cpumask_map[0], cpu_possible_mask);
- return 0;
-}
-early_initcall(numa_init_early);
-
-/*
* numa_init_late() - Initialization initcall
*
* Register NUMA nodes.

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