sched: Change nr_uninterruptible type to unsigned long

JIRA: https://issues.redhat.com/browse/RHEL-107437
Conflicts: Minor context diff in sched.h.

commit 3656978
Author: Aruna Ramakrishna <aruna.ramakrishna@oracle.com>
Date:   Wed Jul 9 17:33:28 2025 +0000

    sched: Change nr_uninterruptible type to unsigned long

    The commit e6fe3f4 ("sched: Make multiple runqueue task counters
    32-bit") changed nr_uninterruptible to an unsigned int. But the
    nr_uninterruptible values for each of the CPU runqueues can grow to
    large numbers, sometimes exceeding INT_MAX. This is valid, if, over
    time, a large number of tasks are migrated off of one CPU after going
    into an uninterruptible state. Only the sum of all nr_interruptible
    values across all CPUs yields the correct result, as explained in a
    comment in kernel/sched/loadavg.c.

    Change the type of nr_uninterruptible back to unsigned long to prevent
    overflows, and thus the miscalculation of load average.

    Fixes: e6fe3f4 ("sched: Make multiple runqueue task counters 32-bit")

    Signed-off-by: Aruna Ramakrishna <aruna.ramakrishna@oracle.com>
    Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
    Link: https://lkml.kernel.org/r/20250709173328.606794-1-aruna.ramakrishna@oracle.com

Signed-off-by: Phil Auld <pauld@redhat.com>

Author: auldp

kernel/sched/loadavg.c

@@ -80,7 +80,7 @@ long calc_load_fold_active(struct rq *this_rq, long adjust)
 	long nr_active, delta = 0;
 
 	nr_active = this_rq->nr_running - adjust;
-	nr_active += (int)this_rq->nr_uninterruptible;
+	nr_active += (long)this_rq->nr_uninterruptible;
 
 	if (nr_active != this_rq->calc_load_active) {
 		delta = nr_active - this_rq->calc_load_active;

kernel/sched/sched.h

@@ -1079,7 +1079,7 @@ struct rq {
 	 * one CPU and if it got migrated afterwards it may decrease
 	 * it on another CPU. Always updated under the runqueue lock:
 	 */
-	unsigned int		nr_uninterruptible;
+	unsigned long 		nr_uninterruptible;
 
 	struct task_struct __rcu	*curr;
 	struct task_struct	*idle;