commit 60b09c51bb upstream.
The effective affinity mask handling has no safety net when the mask is not
updated by the interrupt chip or the mask contains offline CPUs.
If that happens the CPU unplug code fails to migrate interrupts.
Add sanity checks and emit a warning when the mask contains only offline
CPUs.
Fixes: 415fcf1a22 ("genirq/cpuhotplug: Use effective affinity mask")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1710042208400.2406@nanos
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>