diff --git a/scst/include/backport.h b/scst/include/backport.h
index 63659596b..debb5bf7f 100644
--- a/scst/include/backport.h
+++ b/scst/include/backport.h
@@ -776,6 +776,39 @@ static inline void *kmalloc_array(size_t n, size_t size, gfp_t flags)
 }
 #endif
 
+/*
+ * See also commit 8eb8284b4129 ("usercopy: Prepare for usercopy
+ * whitelisting").
+ */
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 23)
+static inline struct kmem_cache *kmem_cache_create_usercopy(const char *name,
+			unsigned int size, unsigned int align,
+			unsigned long flags,
+			unsigned int useroffset, unsigned int usersize,
+			void (*ctor)(void *))
+{
+	return kmem_cache_create(name, size, align, flags, ctor, NULL);
+}
+#elif LINUX_VERSION_CODE < KERNEL_VERSION(4, 16, 0)
+static inline struct kmem_cache *kmem_cache_create_usercopy(const char *name,
+			unsigned int size, unsigned int align,
+			unsigned long flags,
+			unsigned int useroffset, unsigned int usersize,
+			void (*ctor)(void *))
+{
+	return kmem_cache_create(name, size, align, flags, ctor);
+}
+#endif
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 16, 0)
+#define KMEM_CACHE_USERCOPY(__struct, __flags, __field)			\
+		kmem_cache_create_usercopy(#__struct,			\
+			sizeof(struct __struct),			\
+			__alignof__(struct __struct), (__flags),	\
+			offsetof(struct __struct, __field),		\
+			sizeof_field(struct __struct, __field), NULL)
+#endif
+
 /* <linux/t10-pi.h> */
 
 #if LINUX_VERSION_CODE < KERNEL_VERSION(3, 18, 0)
diff --git a/scst/src/dev_handlers/scst_user.c b/scst/src/dev_handlers/scst_user.c
index d213c691a..911796c3a 100644
--- a/scst/src/dev_handlers/scst_user.c
+++ b/scst/src/dev_handlers/scst_user.c
@@ -4212,8 +4212,8 @@ static int __init init_scst_user(void)
 		goto out;
 	}
 
-	user_cmd_cachep = KMEM_CACHE(scst_user_cmd,
-				SCST_SLAB_FLAGS|SLAB_HWCACHE_ALIGN);
+	user_cmd_cachep = KMEM_CACHE_USERCOPY(scst_user_cmd,
+				SCST_SLAB_FLAGS | SLAB_HWCACHE_ALIGN, user_cmd);
 	if (user_cmd_cachep == NULL) {
 		res = -ENOMEM;
 		goto out_dev_cache;
diff --git a/scst/src/dev_handlers/scst_vdisk.c b/scst/src/dev_handlers/scst_vdisk.c
index 8d24696a2..44ceb48f8 100644
--- a/scst/src/dev_handlers/scst_vdisk.c
+++ b/scst/src/dev_handlers/scst_vdisk.c
@@ -3849,27 +3849,20 @@ static int vdisk_sup_vpd(uint8_t *buf, struct scst_cmd *cmd,
 static int vdisk_usn_vpd(uint8_t *buf, struct scst_cmd *cmd,
 			 struct scst_vdisk_dev *virt_dev)
 {
+	uint16_t usn_len, max_len = INQ_BUF_SZ - 4;
+
 	buf[1] = 0x80;
 	if (cmd->tgtt->get_serial) {
-		buf[3] = cmd->tgtt->get_serial(cmd->tgt_dev, &buf[4],
-					       INQ_BUF_SZ - 4);
+		usn_len = cmd->tgtt->get_serial(cmd->tgt_dev, &buf[4], max_len);
 	} else {
-		int usn_len;
-
 		read_lock(&vdisk_serial_rwlock);
 		usn_len = strlen(virt_dev->usn);
-		buf[3] = usn_len;
-#if __GNUC__ -0 >= 8
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wstringop-truncation"
-#endif
-		strncpy(&buf[4], virt_dev->usn, usn_len);
-#if __GNUC__ -0 >= 8
-#pragma GCC diagnostic pop
-#endif
+		WARN_ON_ONCE(usn_len > max_len);
+		memcpy(&buf[4], virt_dev->usn, usn_len);
 		read_unlock(&vdisk_serial_rwlock);
 	}
-	return buf[3] + 4;
+	put_unaligned_be16(usn_len, &buf[2]);
+	return usn_len + 4;
 }
 
 /* Device Identification VPD page (83h) */
diff --git a/scst/src/scst_main.c b/scst/src/scst_main.c
index ea90e6898..274b32b38 100644
--- a/scst/src/scst_main.c
+++ b/scst/src/scst_main.c
@@ -2581,6 +2581,13 @@ static int __init init_scst(void)
 			  sizeof(struct s));				\
 		(p);							\
 	})
+#define INIT_CACHEP_ALIGN_USERCOPY(p, s, f) ({				\
+		(p) = KMEM_CACHE_USERCOPY(s, SCST_SLAB_FLAGS |		\
+					  SLAB_HWCACHE_ALIGN, f);	\
+		TRACE_MEM("Slab create: %s at %p size %zd", #s, (p),	\
+			  sizeof(struct s));				\
+		(p);							\
+	})
 
 	res = -ENOMEM;
 	if (!INIT_CACHEP(scst_mgmt_cachep, scst_mgmt_cmd))
@@ -2596,7 +2603,7 @@ static int __init init_scst(void)
 	}
 	if (!INIT_CACHEP(scst_aen_cachep, scst_aen)) /* read-mostly */
 		goto out_destroy_sense_cache;
-	if (!INIT_CACHEP_ALIGN(scst_cmd_cachep, scst_cmd))
+	if (!INIT_CACHEP_ALIGN_USERCOPY(scst_cmd_cachep, scst_cmd, cdb))
 		goto out_destroy_aen_cache;
 	/* Big enough with read-mostly head and tail */
 	if (!INIT_CACHEP(scst_sess_cachep, scst_session))