[libvirt PATCH 1/2] vircgroupv2: properly free BPF prog and map FDs

[Pavel Hrdina]

When nested cgroup was introduced it did not properly free file
descriptors for BPF prog and map. With nested cgroups we create the BPF
bits in the nested cgroup instead of the VM root cgroup.

This would leak the FDs which would be the last reference to the prog
and map so kernel would not remove the resources as well. It would only
happen once libvirtd process exits.

Fixes: 184245f53b94fc84f727eb6e8a2aa52df02d69c0
Reported-by: Eric Farman <farman at linux.ibm.com>
Signed-off-by: Pavel Hrdina <phrdina at redhat.com>
---
 src/util/vircgroupv2.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/util/vircgroupv2.c b/src/util/vircgroupv2.c
index 248d4047e5..4664492c34 100644
--- a/src/util/vircgroupv2.c
+++ b/src/util/vircgroupv2.c
@@ -523,6 +523,7 @@ static int
 virCgroupV2Remove(virCgroupPtr group)
 {
     g_autofree char *grppath = NULL;
+    virCgroupPtr parent = virCgroupGetNested(group);
     int controller;
 
     /* Don't delete the root group, if we accidentally
@@ -534,7 +535,7 @@ virCgroupV2Remove(virCgroupPtr group)
     if (virCgroupV2PathOfController(group, controller, "", &grppath) < 0)
         return 0;
 
-    if (virCgroupV2DevicesRemoveProg(group) < 0)
+    if (virCgroupV2DevicesRemoveProg(parent) < 0)
         return -1;
 
     return virCgroupRemoveRecursively(grppath);
-- 
2.30.2