genirq/affinity: Consider that CPUs on nodes can be unbalanced

stable inclusion
from stable-v5.10.112
commit 0275c75955d1cdec07bc6d4f6551dbf253c2aaeb
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5HL0X

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=0275c75955d1cdec07bc6d4f6551dbf253c2aaeb

--------------------------------

commit 08d835df upstream.

If CPUs on a node are offline at boot time, the number of nodes is
different when building affinity masks for present cpus and when building
affinity masks for possible cpus. This causes the following problem:

In the case that the number of vectors is less than the number of nodes
there are cases where bits of masks for present cpus are overwritten when
building masks for possible cpus.

Fix this by excluding CPUs, which are not part of the current build mask
(present/possible).

[ tglx: Massaged changelog and added comment ]

Fixes: b8259219 ("genirq/affinity: Spread IRQs to all available NUMA nodes")
Signed-off-by: NRei Yamamoto <yamamoto.rei@jp.fujitsu.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Reviewed-by: NMing Lei <ming.lei@redhat.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20220331003309.10891-1-yamamoto.rei@jp.fujitsu.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>
Acked-by: NXie XiuQi <xiexiuqi@huawei.com>

kernel/irq/affinity.c

@@ -269,8 +269,9 @@ static int __irq_build_affinity_masks(unsigned int startvec,
 	 */
 	if (numvecs <= nodes) {
 		for_each_node_mask(n, nodemsk) {
-			cpumask_or(&masks[curvec].mask, &masks[curvec].mask,
-				   node_to_cpumask[n]);
+			/* Ensure that only CPUs which are in both masks are set */
+			cpumask_and(nmsk, cpu_mask, node_to_cpumask[n]);
+			cpumask_or(&masks[curvec].mask, &masks[curvec].mask, nmsk);
 			if (++curvec == last_affv)
 				curvec = firstvec;
 		}