From: Josh Don <joshdon@google.com>
Date: Wed, 15 Mar 2023 14:40:29 -0700
Subject: [PATCH] cgroup: fix display of forceidle time at root
References: bsc#1012628
Patch-mainline: 6.2.12
Git-commit: fcdb1eda5302599045bb366e679cccb4216f3873

commit fcdb1eda5302599045bb366e679cccb4216f3873 upstream.

We need to reset forceidle_sum to 0 when reading from root, since the
bstat we accumulate into is stack allocated.

To make this more robust, just replace the existing cputime reset with a
memset of the overall bstat.

Signed-off-by: Josh Don <joshdon@google.com>
Fixes: 1fcf54deb767 ("sched/core: add forced idle accounting for cgroups")
Cc: stable@vger.kernel.org # v6.0+
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 kernel/cgroup/rstat.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/kernel/cgroup/rstat.c b/kernel/cgroup/rstat.c
index 793ecff2..7006fc8d 100644
--- a/kernel/cgroup/rstat.c
+++ b/kernel/cgroup/rstat.c
@@ -457,9 +457,7 @@ static void root_cgroup_cputime(struct cgroup_base_stat *bstat)
 	struct task_cputime *cputime = &bstat->cputime;
 	int i;
 
-	cputime->stime = 0;
-	cputime->utime = 0;
-	cputime->sum_exec_runtime = 0;
+	memset(bstat, 0, sizeof(*bstat));
 	for_each_possible_cpu(i) {
 		struct kernel_cpustat kcpustat;
 		u64 *cpustat = kcpustat.cpustat;
-- 
2.35.3