This is a note to let you know that I've just added the patch titled
genirq: Take the proposed affinity at face value if force==true
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-take-the-proposed-affinity-at-face-value-if-force-true.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 17:08:35 +0000
Subject: genirq: Take the proposed affinity at face value if force==true
To: <stable@xxxxxxxxxxxxxxx>, <maz@xxxxxxxxxx>
Cc: <tglx@xxxxxxxxxxxxx>, <lcapitulino@xxxxxxxxx>, Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>, Luiz Capitulino <luizcap@xxxxxxxxxx>
Message-ID: <56bb8afbb97c6ed2364ba49dd0695ce7681aa3ec.1669655291.git.luizcap@xxxxxxxxxx>
From: Luiz Capitulino <luizcap@xxxxxxxxxx>
From: Marc Zyngier <maz@xxxxxxxxxx>
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@xxxxxxxxxxx>
Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Tested-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
Link: https://lore.kernel.org/r/4b7fc13c-887b-a664-26e8-45aed13f048a@xxxxxxxxxxx
Link: https://lore.kernel.org/r/20220414140011.541725-1-maz@xxxxxxxxxx
Signed-off-by: Luiz Capitulino <luizcap@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/irq/manage.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -266,10 +266,16 @@ int irq_do_set_affinity(struct irq_data
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;
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
