From: Marc Zyngier maz@kernel.org
commit c48c8b829d2b966a6649827426bcdba082ccf922 upstream.
Although setting the affinity of an interrupt to a set of CPUs that doesn't have any online CPU is generally frowned apon, there are a few limited cases where such affinity is set from a CPUHP notifier, setting the affinity to a CPU that isn't online yet.
The saving grace is that this is always done using the 'force' attribute, which gives a hint that the affinity setting can be outside of the online CPU mask and the callsite set this flag with the knowledge that the underlying interrupt controller knows to handle it.
This restores the expected behaviour on Marek's system.
Fixes: 33de0aa4bae9 ("genirq: Always limit the affinity to online CPUs") Reported-by: Marek Szyprowski m.szyprowski@samsung.com Signed-off-by: Marc Zyngier maz@kernel.org Signed-off-by: Thomas Gleixner tglx@linutronix.de Tested-by: Marek Szyprowski m.szyprowski@samsung.com Link: https://lore.kernel.org/r/4b7fc13c-887b-a664-26e8-45aed13f048a@samsung.com Link: https://lore.kernel.org/r/20220414140011.541725-1-maz@kernel.org
Signed-off-by: Luiz Capitulino luizcap@amazon.com --- kernel/irq/manage.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index a1727cdaebed..9862372e0f01 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -266,10 +266,16 @@ int irq_do_set_affinity(struct irq_data *data, const struct cpumask *mask, prog_mask = mask; }
- /* Make sure we only provide online CPUs to the irqchip */ + /* + * Make sure we only provide online CPUs to the irqchip, + * unless we are being asked to force the affinity (in which + * case we do as we are told). + */ cpumask_and(&tmp_mask, prog_mask, cpu_online_mask); - if (!cpumask_empty(&tmp_mask)) + if (!force && !cpumask_empty(&tmp_mask)) ret = chip->irq_set_affinity(data, &tmp_mask, force); + else if (force) + ret = chip->irq_set_affinity(data, mask, force); else ret = -EINVAL;