With commit dc20b2d52653 ("x86/idt: Move interrupt gate initialization to IDT code") non assigned system vectors are also marked as used in 'used_vectors' (now 'system_vectors') bitmap. This makes checks in arch_show_interrupts() whether a particular system vector is allocated to always pass and e.g. 'Hyper-V reenlightenment interrupts' entry always shows up in /proc/interrupts.
Another side effect of having all unassigned system vectors marked as used is that irq_matrix_debug_show() will wrongly count them among 'System' vectors. As we now make sure alloc_intr_gate() is not called after init, it is possible to leave unused entries in 'system_vectors' unset to fix the issues. Signed-off-by: Vitaly Kuznetsov <vkuzn...@redhat.com> --- arch/x86/kernel/idt.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/idt.c b/arch/x86/kernel/idt.c index f95c3be00e5a..28500ccb835c 100644 --- a/arch/x86/kernel/idt.c +++ b/arch/x86/kernel/idt.c @@ -321,7 +321,11 @@ void __init idt_setup_apic_and_irq_gates(void) #ifdef CONFIG_X86_LOCAL_APIC for_each_clear_bit_from(i, system_vectors, NR_VECTORS) { - set_bit(i, system_vectors); + /* + * Don't set the non assigned system vectors in the + * system_vectors bitmap. Otherwise they show up in + * /proc/interrupts. + */ entry = spurious_entries_start + 8 * (i - FIRST_SYSTEM_VECTOR); set_intr_gate(i, entry); } -- 2.25.3