DEBUG_HOTPLUG_CPU0 debug feature offlines a CPU as early as possible allowing userspace to boot up without that CPU (so that it is possible to check for unwanted dependencies towards the offlined CPU). After doing so it emits a "CPU %u is now offline" pr_info, which is not enough descriptive of why the CPU was offlined (e.g., one might be running with a config that triggered some problem, not being aware that CONFIG_DEBUG_ HOTPLUG_CPU0 is set).
Add a bit more of informative text to the pr_info, so that it is immediately obvious why a CPU has been offlined in early boot stages. Signed-off-by: Juri Lelli <juri.le...@redhat.com> --- Got to scratch my head a bit while debugging a WARNING splat related to the offlining of CPU0. Without being aware yet of this debug option it wasn't immediately obvious why CPU0 was being offlined by the kernel. Hope this makes sense and is acceptable. :-) --- arch/x86/kernel/topology.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/topology.c b/arch/x86/kernel/topology.c index 738bf42b0218..c3c2400e30b1 100644 --- a/arch/x86/kernel/topology.c +++ b/arch/x86/kernel/topology.c @@ -71,7 +71,8 @@ int _debug_hotplug_cpu(int cpu, int action) case 0: ret = cpu_down(cpu); if (!ret) { - pr_info("CPU %u is now offline\n", cpu); + pr_info("DEBUG_HOTPLUG_CPU0: CPU %u is now offline\n", + cpu); dev->offline = true; kobject_uevent(&dev->kobj, KOBJ_OFFLINE); } else -- 2.17.2