update code for runc related changes part 2

Signed-off-by: Arjun Raja Yogidas <arjunry@amazon.com>

Author: coderbirju

.buildkite/pipeline.yml

@@ -75,7 +75,8 @@ steps:
     artifact_paths:
       - "runtime/logs/*"
     command:
-      - make -C runtime integ-test FICD_DM_POOL=build_${BUILDKITE_BUILD_NUMBER}_runtime
+      # Temporarily only run TestStopVM_Isolated to validate runc 1.2 fix
+      - make -C runtime integ-test-TestStopVM_Isolated FICD_DM_POOL=build_${BUILDKITE_BUILD_NUMBER}_runtime
     retry:
       automatic:
         - exit_status: "*"

runtime/runc_jailer.go

@@ -675,13 +675,31 @@ func (j runcJailer) Stop(force bool) error {
 	return j.runcClient.Kill(j.ctx, j.vmID, int(signal), &runc.KillOpts{All: true})
 }
 
-// IsRunning checks if the runc container is still running.
+// IsRunning checks if the runc container's init process is still alive and not a zombie.
 func (j *runcJailer) IsRunning(ctx context.Context) bool {
 	state, err := j.runcClient.State(ctx, j.vmID)
 	if err != nil {
 		return false
 	}
-	return state.Status == "running" || state.Status == "created" || state.Status == "paused"
+	if state.Pid <= 0 {
+		return false
+	}
+	// Check /proc/[pid]/stat to see if process is running (not zombie or dead)
+	statPath := fmt.Sprintf("/proc/%d/stat", state.Pid)
+	data, err := os.ReadFile(statPath)
+	if err != nil {
+		return false // Process doesn't exist
+	}
+	// Format: pid (comm) state ...
+	// Find the state character after the last ')'
+	statStr := string(data)
+	idx := strings.LastIndex(statStr, ")")
+	if idx == -1 || idx+2 >= len(statStr) {
+		return false
+	}
+	procState := statStr[idx+2] // Skip ") " to get state char
+	// Z = zombie, X = dead, x = dead
+	return procState != 'Z' && procState != 'X' && procState != 'x'
 }
 
 // setupCacheTopology will copy indexed contents from the cacheTopologyPath to