This is a note to let you know that I've just added the patch titled
genirq: Always limit the affinity to online CPUs
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
genirq-always-limit-the-affinity-to-online-cpus.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Wed Nov 30 06:09:32 PM CET 2022
From: Luiz Capitulino <luizcap@xxxxxxxxxx>
Date: Mon, 28 Nov 2022 17:08:33 +0000
Subject: genirq: Always limit the affinity to online CPUs
To: <stable@xxxxxxxxxxxxxxx>, <maz@xxxxxxxxxx>
Cc: <tglx@xxxxxxxxxxxxx>, <lcapitulino@xxxxxxxxx>, Luiz Capitulino <luizcap@xxxxxxxxxx>
Message-ID: <9a311a850001dc60bf1f83a21f43f9567d658c15.1669655291.git.luizcap@xxxxxxxxxx>
From: Luiz Capitulino <luizcap@xxxxxxxxxx>
From: Marc Zyngier <maz@xxxxxxxxxx>
commit 33de0aa4bae982ed6f7c777f86b5af3e627ac937 upstream.
[ Fixed small conflicts due to the HK_FLAG_MANAGED_IRQ flag been
renamed on upstream ]
When booting with maxcpus=<small number> (or even loading a driver
while most CPUs are offline), it is pretty easy to observe managed
affinities containing a mix of online and offline CPUs being passed
to the irqchip driver.
This means that the irqchip cannot trust the affinity passed down
from the core code, which is a bit annoying and requires (at least
in theory) all drivers to implement some sort of affinity narrowing.
In order to address this, always limit the cpumask to the set of
online CPUs.
Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20220405185040.206297-3-maz@xxxxxxxxxx
Signed-off-by: Luiz Capitulino <luizcap@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/irq/manage.c | 25 +++++++++++++++++--------
1 file changed, 17 insertions(+), 8 deletions(-)
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -222,11 +222,16 @@ int irq_do_set_affinity(struct irq_data
{
struct irq_desc *desc = irq_data_to_desc(data);
struct irq_chip *chip = irq_data_get_irq_chip(data);
+ const struct cpumask *prog_mask;
int ret;
+ static DEFINE_RAW_SPINLOCK(tmp_mask_lock);
+ static struct cpumask tmp_mask;
+
if (!chip || !chip->irq_set_affinity)
return -EINVAL;
+ raw_spin_lock(&tmp_mask_lock);
/*
* If this is a managed interrupt and housekeeping is enabled on
* it check whether the requested affinity mask intersects with
@@ -248,24 +253,28 @@ int irq_do_set_affinity(struct irq_data
*/
if (irqd_affinity_is_managed(data) &&
housekeeping_enabled(HK_FLAG_MANAGED_IRQ)) {
- const struct cpumask *hk_mask, *prog_mask;
-
- static DEFINE_RAW_SPINLOCK(tmp_mask_lock);
- static struct cpumask tmp_mask;
+ const struct cpumask *hk_mask;
hk_mask = housekeeping_cpumask(HK_FLAG_MANAGED_IRQ);
- raw_spin_lock(&tmp_mask_lock);
cpumask_and(&tmp_mask, mask, hk_mask);
if (!cpumask_intersects(&tmp_mask, cpu_online_mask))
prog_mask = mask;
else
prog_mask = &tmp_mask;
- ret = chip->irq_set_affinity(data, prog_mask, force);
- raw_spin_unlock(&tmp_mask_lock);
} else {
- ret = chip->irq_set_affinity(data, mask, force);
+ prog_mask = mask;
}
+
+ /* Make sure we only provide online CPUs to the irqchip */
+ cpumask_and(&tmp_mask, prog_mask, cpu_online_mask);
+ if (!cpumask_empty(&tmp_mask))
+ ret = chip->irq_set_affinity(data, &tmp_mask, force);
+ else
+ ret = -EINVAL;
+
+ raw_spin_unlock(&tmp_mask_lock);
+
switch (ret) {
case IRQ_SET_MASK_OK:
case IRQ_SET_MASK_OK_DONE:
Patches currently in stable-queue which might be from luizcap@xxxxxxxxxx are
queue-5.15/genirq-take-the-proposed-affinity-at-face-value-if-force-true.patch
queue-5.15/genirq-always-limit-the-affinity-to-online-cpus.patch
queue-5.15/genirq-msi-shutdown-managed-interrupts-with-unsatifiable-affinities.patch
queue-5.15/irqchip-gic-v3-always-trust-the-managed-affinity-provided-by-the-core-code.patch
