On Tue, 23 Jan 2024, Huang Shijie wrote:
During the kernel booting, the generic cpu_to_node() is called too early in
arm64, powerpc and riscv when CONFIG_NUMA is enabled.
For arm64/powerpc/riscv, there are at least four places in the common code
where the generic cpu_to_node() is called before it is initialized:
1.) early_trace_init() in kernel/trace/trace.c
2.) sched_init() in kernel/sched/core.c
3.) init_sched_fair_class() in kernel/sched/fair.c
4.) workqueue_init_early() in kernel/workqueue.c
In order to fix the bug, the patch changes generic cpu_to_node to
function pointer, and export it for kernel modules.
Introduce smp_prepare_boot_cpu_start() to wrap the original
smp_prepare_boot_cpu(), and set cpu_to_node with early_cpu_to_node.
Introduce smp_prepare_cpus_done() to wrap the original smp_prepare_cpus(),
and set the cpu_to_node to formal _cpu_to_node().
Would you please fix this cleanly without a function pointer?
What I think needs to be done is a patch series.
1. Instrument cpu_to_node so that some warning is issued if it is used too
early. Preloading the array with NUMA_NO_NODE would allow us to do that.
2. Implement early_cpu_to_node on platforms that currently do not have it.
3. A series of patches that fix each place where cpu_to_node is used too
early.
