Interrupt child procs when interrupting kernel (#16319)

src/kernels/raw/launcher/kernelProcess.node.ts

@@ -152,6 +152,7 @@ export class KernelProcess extends ObservableDisposable implements IKernelProces
         ) {
             logger.info('Interrupting kernel via SIGINT');
             if (this._process.pid) {
+                await this.interruptChildProcesses(this._process.pid);
                 kill(this._process.pid, 'SIGINT');
             }
         } else if (
@@ -407,6 +408,33 @@ export class KernelProcess extends ObservableDisposable implements IKernelProces
         }
     }
 
+    private async interruptChildProcesses(pid: number) {
+        // Do not remove this code, in in unit tests we end up running this,
+        // then we run into the danger of kill all of the processes on the machine.
+        // because calling `pidtree` without a pid will return all pids and hence everything ends up getting killed.
+        if (!ProcessService.isAlive(pid)) {
+            return;
+        }
+        try {
+            if (this.platform.isWindows) {
+                return;
+            } else {
+                await new Promise<void>((resolve) => {
+                    pidtree(pid, (ex: unknown, pids: number[]) => {
+                        if (ex) {
+                            logger.warn(`Failed to interrupt children for ${pid}`, ex);
+                        } else {
+                            pids.forEach((procId) => kill(procId, 'SIGINT'));
+                        }
+                        resolve();
+                    });
+                });
+            }
+        } catch (ex) {
+            logger.warn(`Failed to interrupt children for ${pid}`, ex);
+        }
+    }
+
     private sendToOutput(data: string) {
         if (this.outputChannel) {
             this.outputChannel.append(data);