The commit e6fe3f422be1 ("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: e6fe3f422be1 ("sched: Make multiple runqueue task counters 32-bit")
Signed-off-by: Aruna Ramakrishna <aruna.ramakrishna@oracle.com>
---
kernel/sched/loadavg.c | 2 +-
kernel/sched/sched.h | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/sched/loadavg.c b/kernel/sched/loadavg.c
index c48900b856a2..52ca8e268cfc 100644
--- a/kernel/sched/loadavg.c
+++ b/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;
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 475bb5998295..83e3aa917142 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -1149,7 +1149,7 @@ 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;
union {
struct task_struct __rcu *donor; /* Scheduler context */
base-commit: 86731a2a651e58953fc949573895f2fa6d456841
prerequisite-patch-id: dd6db7012c5094dec89e689ba56fd3551d2b4a40
--
2.43.5