Patch "s390/cputime: fix guest/irq/softirq times after CPU hotplug" has been added to the 4.13-stable tree

Patch "s390/cputime: fix guest/irq/softirq times after CPU hotplug" has been added to the 4.13-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    s390/cputime: fix guest/irq/softirq times after CPU hotplug

to the 4.13-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     s390-cputime-fix-guest-irq-softirq-times-after-cpu-hotplug.patch
and it can be found in the queue-4.13 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From b7662eef14caf4f582d453d45395825b5a8f594c Mon Sep 17 00:00:00 2001
From: Christian Borntraeger <borntraeger@de.ibm.com>
Date: Wed, 4 Oct 2017 14:46:17 +0200
Subject: s390/cputime: fix guest/irq/softirq times after CPU hotplug

From: Christian Borntraeger <borntraeger@de.ibm.com>

commit b7662eef14caf4f582d453d45395825b5a8f594c upstream.

On CPU hotplug some cpu stats contain bogus values:

$ cat /proc/stat
cpu 0 0 49 1280 0 0 0 3 0 0
cpu0 0 0 49 618 0 0 0 3 0 0
cpu1 0 0 0 662 0 0 0 0 0 0
[...]
$ echo 0 > /sys/devices/system/cpu/cpu1/online
$ echo 1 > /sys/devices/system/cpu/cpu1/online
$ cat /proc/stat
cpu 0 0 49 3200 0 450359962737 450359962737 3 0 0
cpu0 0 0 49 1956 0 0 0 3 0 0
cpu1 0 0 0 1244 0 450359962737 450359962737 0 0 0
[...]

pcpu_attach_task() needs the same assignments as vtime_task_switch.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Fixes: b7394a5f4ce9 ("sched/cputime, s390: Implement delayed accounting of system time")
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/s390/kernel/smp.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -293,7 +293,10 @@ static void pcpu_attach_task(struct pcpu
 	lc->lpp = LPP_MAGIC;
 	lc->current_pid = tsk->pid;
 	lc->user_timer = tsk->thread.user_timer;
+	lc->guest_timer = tsk->thread.guest_timer;
 	lc->system_timer = tsk->thread.system_timer;
+	lc->hardirq_timer = tsk->thread.hardirq_timer;
+	lc->softirq_timer = tsk->thread.softirq_timer;
 	lc->steal_timer = 0;
 }
 


Patches currently in stable-queue which might be from borntraeger@de.ibm.com are

queue-4.13/s390-cputime-fix-guest-irq-softirq-times-after-cpu-hotplug.patch