The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x 597704e201068db3d104de3c7a4d447ff8209127 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2025060228-output-connected-12d9@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 597704e201068db3d104de3c7a4d447ff8209127 Mon Sep 17 00:00:00 2001 From: Robin Murphy robin.murphy@arm.com Date: Mon, 12 May 2025 18:11:54 +0100 Subject: [PATCH] perf/arm-cmn: Initialise cmn->cpu earlier

For all the complexity of handling affinity for CPU hotplug, what we've apparently managed to overlook is that arm_cmn_init_irqs() has in fact always been setting the *initial* affinity of all IRQs to CPU 0, not the CPU we subsequently choose for event scheduling. Oh dear.

Cc: stable@vger.kernel.org Fixes: 0ba64770a2f2 ("perf: Add Arm CMN-600 PMU driver") Signed-off-by: Robin Murphy robin.murphy@arm.com Reviewed-by: Ilkka Koskinen ilkka@os.amperecomputing.com Link: https://lore.kernel.org/r/b12fccba6b5b4d2674944f59e4daad91cd63420b.174706991... Signed-off-by: Will Deacon will@kernel.org

diff --git a/drivers/perf/arm-cmn.c b/drivers/perf/arm-cmn.c index 83f4ef985255..668c581e932a 100644 --- a/drivers/perf/arm-cmn.c +++ b/drivers/perf/arm-cmn.c @@ -2551,6 +2551,7 @@ static int arm_cmn_probe(struct platform_device *pdev)

cmn->dev = &pdev->dev; cmn->part = (unsigned long)device_get_match_data(cmn->dev); + cmn->cpu = cpumask_local_spread(0, dev_to_node(cmn->dev)); platform_set_drvdata(pdev, cmn);

if (cmn->part == PART_CMN600 && has_acpi_companion(cmn->dev)) { @@ -2578,7 +2579,6 @@ static int arm_cmn_probe(struct platform_device *pdev) if (err) return err;

- cmn->cpu = cpumask_local_spread(0, dev_to_node(cmn->dev)); cmn->pmu = (struct pmu) { .module = THIS_MODULE, .parent = cmn->dev,