From 02b2342b6b5e45e3f41cb145521f53118ba8430f Mon Sep 17 00:00:00 2001
Message-Id: <02b2342b6b5e45e3f41cb145521f53118ba8430f@dist-git>
From: Pavel Hrdina <phrdina@redhat.com>
Date: Mon, 1 Jul 2019 17:08:21 +0200
Subject: [PATCH] util: vircgroupv2: don't error out if enabling controller
 fails
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Currently CPU controller cannot be enabled if there is any real-time
task running and is assigned to non-root cgroup which is the case on
several distributions with graphical environment.

Instead of erroring out treat it as the controller is not available.

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
(cherry picked from commit 1d49cdcd116186e079db5668893da17f56141652)

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1689297

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
Message-Id: <4a10dec59ca8cf5a2f81acf70d43f48b0a3bfd82.1561993100.git.phrdina@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
---
 src/util/vircgroupv2.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/src/util/vircgroupv2.c b/src/util/vircgroupv2.c
index a67d5cfe04..e1ab1849ba 100644
--- a/src/util/vircgroupv2.c
+++ b/src/util/vircgroupv2.c
@@ -437,6 +437,8 @@ virCgroupV2MakeGroup(virCgroupPtr parent ATTRIBUTE_UNUSED,
         } else {
             size_t i;
             for (i = 0; i < VIR_CGROUP_CONTROLLER_LAST; i++) {
+                int rc;
+
                 if (!virCgroupV2HasController(parent, i))
                     continue;
 
@@ -444,8 +446,17 @@ virCgroupV2MakeGroup(virCgroupPtr parent ATTRIBUTE_UNUSED,
                 if (i == VIR_CGROUP_CONTROLLER_CPUACCT)
                     continue;
 
-                if (virCgroupV2EnableController(parent, i, true) < 0)
+                rc = virCgroupV2EnableController(parent, i, false);
+                if (rc < 0) {
+                    if (rc == -2) {
+                        virResetLastError();
+                        VIR_DEBUG("failed to enable '%s' controller, skipping",
+                                  virCgroupV2ControllerTypeToString(i));
+                        group->unified.controllers &= ~(1 << i);
+                        continue;
+                    }
                     return -1;
+                }
             }
         }
     }
-- 
2.22.0