From: Kyle Hale <kh@u.northwestern.edu>
Date: Sat, 7 Jul 2012 22:47:17 +0000 (-0500)
Subject: Fail gracefully on VM create or free errors
X-Git-Url: http://v3vee.org/palacios/gitweb/gitweb.cgi?a=commitdiff_plain;h=47dc84c2e6854edb598062918070b2da97e8f10a;p=palacios.git

Fail gracefully on VM create or free errors
---

diff --git a/linux_module/main.c b/linux_module/main.c
index c432e3c..57917e0 100644
--- a/linux_module/main.c
+++ b/linux_module/main.c
@@ -89,16 +89,14 @@ static long v3_dev_ioctl(struct file * filp,
 
 	    if (vm_minor == -1) {
 		ERROR("Palacios Error: Too many VMs are currently running\n");
-		palacios_free(guest);
-		return -EFAULT;
+		goto out_err;
 	    }
 
 	    guest->vm_dev = MKDEV(v3_major_num, vm_minor);
 
 	    if (copy_from_user(&user_image, argp, sizeof(struct v3_guest_img))) {
 		ERROR("Palacios Error: copy from user error getting guest image...\n");
-		palacios_free(guest);
-		return -EFAULT;
+		goto out_err1;
 	    }
 
 	    guest->img_size = user_image.size;
@@ -108,14 +106,12 @@ static long v3_dev_ioctl(struct file * filp,
 
 	    if (IS_ERR(guest->img)) {
 		ERROR("Palacios Error: Could not allocate space for guest image\n");
-		palacios_free(guest);
-		return -EFAULT;
+		goto out_err1;
 	    }
 
 	    if (copy_from_user(guest->img, user_image.guest_data, guest->img_size)) {
 		ERROR("Palacios: Error loading guest data\n");
-		palacios_free(guest);
-		return -EFAULT;
+		goto out_err2;
 	    }	   
 
 	    strncpy(guest->name, user_image.name, 127);
@@ -124,18 +120,32 @@ static long v3_dev_ioctl(struct file * filp,
 
 	    if (create_palacios_vm(guest) == -1) {
 		ERROR("Palacios: Error creating guest\n");
-                vfree(guest->img);
-		palacios_free(guest);
-		return -EFAULT;
+		goto out_err2;
 	    }
 
 	    return vm_minor;
+
+
+out_err2:
+            vfree(guest->img);
+out_err1:
+            guest_map[vm_minor] = NULL; 
+out_err:
+            palacios_free(guest);
+
+            return -1;
+
 	    break;
 	}
 	case V3_FREE_GUEST: {
 	    unsigned long vm_idx = arg;
 	    struct v3_guest * guest = guest_map[vm_idx];
 
+	    if (!guest) {
+		ERROR("No VM at index %ld\n",vm_idx);
+		return -1;
+	    }
+
 	    INFO("Freeing VM (%s) (%p)\n", guest->name, guest);
 
 	    free_palacios_vm(guest);
diff --git a/linux_module/vm.c b/linux_module/vm.c
index 842d472..1e9b275 100644
--- a/linux_module/vm.c
+++ b/linux_module/vm.c
@@ -303,16 +303,18 @@ extern u32 frees;
 int create_palacios_vm(struct v3_guest * guest)  {
     int err;
 
-    init_vm_extensions(guest);
+    if (init_vm_extensions(guest) < 0) {
+        WARNING("palacios: failed to initialize extensions\n");
+        return -1;
+    }
 
     guest->v3_ctx = v3_create_vm(guest->img, (void *)guest, guest->name);
 
     if (guest->v3_ctx == NULL) { 
 	WARNING("palacios: failed to create vm\n");
-	return -1;
+        goto out_err;
     }
 
-
     NOTICE("Creating VM device: Major %d, Minor %d\n", MAJOR(guest->vm_dev), MINOR(guest->vm_dev));
 
     cdev_init(&(guest->cdev), &v3_vm_fops);
@@ -326,20 +328,25 @@ int create_palacios_vm(struct v3_guest * guest)  {
 
     if (err) {
 	WARNING("Fails to add cdev\n");
-	v3_free_vm(guest->v3_ctx);
-	return -1;
+        goto out_err1;
     }
 
     if (device_create(v3_class, NULL, guest->vm_dev, guest, "v3-vm%d", MINOR(guest->vm_dev)) == NULL){
 	WARNING("Fails to create device\n");
-	cdev_del(&(guest->cdev));
-	v3_free_vm(guest->v3_ctx);
-	return -1;
+        goto out_err2;
     }
 
     NOTICE("palacios: vm created at /dev/v3-vm%d\n", MINOR(guest->vm_dev));
 
     return 0;
+
+out_err2:
+    cdev_del(&(guest->cdev));
+out_err1:
+    v3_free_vm(guest->v3_ctx);
+out_err:
+    deinit_vm_extensions(guest);
+    return -1;
 }