common_interrupt: No irq handler for vector

From: Shuah Khan <skhan@linuxfoundation.org>
To: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	"H. Peter Anvin" <hpa@zytor.com>
Cc: "x86@kernel.org" <x86@kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Shuah Khan <skhan@linuxfoundation.org>
Subject: common_interrupt: No irq handler for vector
Date: Fri, 11 Dec 2020 13:41:13 -0700	[thread overview]
Message-ID: <9741d93c-3cd1-c4ef-74bb-7f635231c778@linuxfoundation.org> (raw)

I am debugging __common_interrupt: 1.55 No irq handler for vector
messages and noticed comments and code don't agree:

arch/x86/kernel/apic/msi.c: msi_set_affinity() says:

  * If the vector is in use then the installed device handler will
  * denote it as spurious which is no harm as this is a rare event
  * and interrupt handlers have to cope with spurious interrupts
  * anyway. If the vector is unused, then it is marked so it won't
  * trigger the 'No irq handler for vector' warning in
  * common_interrupt().

common_interrupt() prints message if vector is unused: VECTOR_UNUSED

ack_APIC_irq();

if (desc == VECTOR_UNUSED) {
     pr_emerg_ratelimited("%s: %d.%u No irq handler for vector\n",
                           __func__, smp_processor_id(), vector);
}

Something wrong here?

thanks,
-- Shuah