4.18-stable review patch. If anyone has any objections, please let me know.
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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.