fix panic due to nil dereference cgroups v2

djdongjin · k8s-infra-cherrypick-robot · commit 3ba2df924a3f · 2024-12-05T01:53:43.000Z
Signed-off-by: Jin Dong &lt;djdongjin95@gmail.com&gt;
diff --git a/cmd/containerd-shim-runc-v2/runc/container.go b/cmd/containerd-shim-runc-v2/runc/container.go
@@ -146,24 +146,9 @@ func NewContainer(ctx context.Context, platform stdio.Platform, r *task.CreateTa
 	}
 	pid := p.Pid()
 	if pid > 0 {
-		var cg interface{}
-		if cgroups.Mode() == cgroups.Unified {
-			g, err := cgroupsv2.PidGroupPath(pid)
-			if err != nil {
-				log.G(ctx).WithError(err).Errorf("loading cgroup2 for %d", pid)
-				return container, nil
-			}
-			cg, err = cgroupsv2.Load(g)
-			if err != nil {
-				log.G(ctx).WithError(err).Errorf("loading cgroup2 for %d", pid)
-			}
-		} else {
-			cg, err = cgroup1.Load(cgroup1.PidPath(pid))
-			if err != nil {
-				log.G(ctx).WithError(err).Errorf("loading cgroup for %d", pid)
-			}
+		if cg, err := loadProcessCgroup(ctx, pid); err == nil {
+			container.cgroup = cg
 		}
-		container.cgroup = cg
 	}
 	return container, nil
 }
@@ -367,23 +352,9 @@ func (c *Container) Start(ctx context.Context, r *task.StartRequest) (process.Pr
 		return p, err
 	}
 	if c.Cgroup() == nil && p.Pid() > 0 {
-		var cg interface{}
-		if cgroups.Mode() == cgroups.Unified {
-			g, err := cgroupsv2.PidGroupPath(p.Pid())
-			if err != nil {
-				log.G(ctx).WithError(err).Errorf("loading cgroup2 for %d", p.Pid())
-			}
-			cg, err = cgroupsv2.Load(g)
-			if err != nil {
-				log.G(ctx).WithError(err).Errorf("loading cgroup2 for %d", p.Pid())
-			}
-		} else {
-			cg, err = cgroup1.Load(cgroup1.PidPath(p.Pid()))
-			if err != nil {
-				log.G(ctx).WithError(err).Errorf("loading cgroup for %d", p.Pid())
-			}
+		if cg, err := loadProcessCgroup(ctx, p.Pid()); err == nil {
+			c.cgroup = cg
 		}
-		c.cgroup = cg
 	}
 	return p, nil
 }
@@ -512,3 +483,25 @@ func (c *Container) HasPid(pid int) bool {
 	}
 	return false
 }
+
+func loadProcessCgroup(ctx context.Context, pid int) (cg interface{}, err error) {
+	if cgroups.Mode() == cgroups.Unified {
+		g, err := cgroupsv2.PidGroupPath(pid)
+		if err != nil {
+			log.G(ctx).WithError(err).Errorf("loading cgroup2 for %d", pid)
+			return nil, err
+		}
+		cg, err = cgroupsv2.Load(g)
+		if err != nil {
+			log.G(ctx).WithError(err).Errorf("loading cgroup2 for %d", pid)
+			return nil, err
+		}
+	} else {
+		cg, err = cgroup1.Load(cgroup1.PidPath(pid))
+		if err != nil {
+			log.G(ctx).WithError(err).Errorf("loading cgroup for %d", pid)
+			return nil, err
+		}
+	}
+	return cg, nil
+}
