From 00592c2f0c07db93ff9370c60ae4f11967d8d5ea Mon Sep 17 00:00:00 2001
From: Fothsid <18036123+Fothsid@users.noreply.github.com>
Date: Thu, 5 Mar 2026 13:31:47 +0100
Subject: [PATCH] fix: check for EPERM when setting IRQ affinity

Kernel version v6.12 changed the return code of the
write_irq_affinity() function in case if affinity cannot
be set for the specified IRQ. Used to be EIO, now it's EPERM.

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=eb29369fa543e7d5557c19ebecf072244bb14815

Resolves: RHEL-153655
---
 tuned/plugins/plugin_scheduler.py | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/tuned/plugins/plugin_scheduler.py b/tuned/plugins/plugin_scheduler.py
index ca0b8eb..72aeb87 100644
--- a/tuned/plugins/plugin_scheduler.py
+++ b/tuned/plugins/plugin_scheduler.py
@@ -1317,12 +1317,13 @@ class SchedulerPlugin(base.Plugin):
 				f.write(affinity_hex)
 			return 0
 		except (OSError, IOError) as e:
-			# EIO is returned by
+			# EPERM is returned by
 			# kernel/irq/proc.c:write_irq_affinity() if changing
 			# the affinity is not supported
-			# (at least on kernels 3.10 and 4.18)
-			if hasattr(e, "errno") and e.errno == errno.EIO \
-					and not restoring:
+			# Before kernel v6.12, write_irq_affinity() returned EIO
+			# instead of EPERM, hence the check for both error codes.
+			if hasattr(e, "errno") and (e.errno == errno.EIO \
+					or e.errno == errno.EPERM) and not restoring:
 				log.debug("Setting SMP affinity of IRQ %s is not supported"
 						% irq)
 				return -2