linux-kernel - [PATCH 5.4 08/60] s390/vtime: fix increased steal time accounting

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Date:   Mon, 22 Mar 2021 13:27:56 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Sabine Forkel <sabine.forkel@...ibm.com>,
        Heiko Carstens <hca@...ux.ibm.com>,
        Gerald Schaefer <gerald.schaefer@...ux.ibm.com>
Subject: [PATCH 5.4 08/60] s390/vtime: fix increased steal time accounting

From: Gerald Schaefer <gerald.schaefer@...ux.ibm.com>

commit d54cb7d54877d529bc1e0e1f47a3dd082f73add3 upstream.

Commit 152e9b8676c6e ("s390/vtime: steal time exponential moving average")
inadvertently changed the input value for account_steal_time() from
"cputime_to_nsecs(steal)" to just "steal", resulting in broken increased
steal time accounting.

Fix this by changing it back to "cputime_to_nsecs(steal)".

Fixes: 152e9b8676c6e ("s390/vtime: steal time exponential moving average")
Cc: <stable@...r.kernel.org> # 5.1
Reported-by: Sabine Forkel <sabine.forkel@...ibm.com>
Reviewed-by: Heiko Carstens <hca@...ux.ibm.com>
Signed-off-by: Gerald Schaefer <gerald.schaefer@...ux.ibm.com>
Signed-off-by: Heiko Carstens <hca@...ux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 arch/s390/kernel/vtime.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/s390/kernel/vtime.c
+++ b/arch/s390/kernel/vtime.c
@@ -217,7 +217,7 @@ void vtime_flush(struct task_struct *tsk
 	avg_steal = S390_lowcore.avg_steal_timer / 2;
 	if ((s64) steal > 0) {
 		S390_lowcore.steal_timer = 0;
-		account_steal_time(steal);
+		account_steal_time(cputime_to_nsecs(steal));
 		avg_steal += steal;
 	}
 	S390_lowcore.avg_steal_timer = avg_steal;