diff --git a/scst/include/backport.h b/scst/include/backport.h
index 3348bd080..ca0d60682 100644
--- a/scst/include/backport.h
+++ b/scst/include/backport.h
@@ -449,7 +449,7 @@ kernel_read_backport(struct file *file, void *buf, size_t count, loff_t *pos)
  * See also commit 7bb307e894d5 ("export kernel_write(), convert open-coded
  * instances") # v3.10.
  */
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 10, 0)
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 10, 0) && !defined(RHEL_MAJOR)
 static inline ssize_t
 kernel_write_backport(struct file *file, void *buf, size_t count, loff_t *pos)
 {
diff --git a/scst/src/scst_lib.c b/scst/src/scst_lib.c
index 0aeed0ae8..e55cc87f4 100644
--- a/scst/src/scst_lib.c
+++ b/scst/src/scst_lib.c
@@ -5966,6 +5966,8 @@ ssize_t scst_read(struct file *file, void *buf, size_t count, loff_t *pos)
 
 	return scst_readv(file, &iov, 1, pos);
 #else
+	WARN_ON_ONCE(scst_cmp_fs_ds() != 0);
+
 	return vfs_read(file, (void __force __user *)buf, count, pos);
 #endif
 }
@@ -5984,6 +5986,8 @@ ssize_t scst_write(struct file *file, const void *buf, size_t count,
 
 	return scst_writev(file, &iov, 1, pos);
 #else
+	WARN_ON_ONCE(scst_cmp_fs_ds() != 0);
+
 	return vfs_write(file, (void __force __user *)buf, count, pos);
 #endif
 }
@@ -6011,8 +6015,12 @@ ssize_t scst_readv(struct file *file, const struct iovec *vec,
 #elif LINUX_VERSION_CODE >= KERNEL_VERSION(4, 6, 0) ||	\
 	(defined(CONFIG_SUSE_KERNEL) &&			\
 	LINUX_VERSION_CODE >= KERNEL_VERSION(4, 4, 0))
+	WARN_ON_ONCE(scst_cmp_fs_ds() != 0);
+
 	return vfs_readv(file, (const struct iovec __user *)vec, vlen, pos, 0);
 #else
+	WARN_ON_ONCE(scst_cmp_fs_ds() != 0);
+
 	return vfs_readv(file, (const struct iovec __user *)vec, vlen, pos);
 #endif
 }