I feel I should point out this entire chain:
http://lkml.org/lkml/2014/4/2/415In which Systemd decides to make passing ``debug'' to the kernel command line completely useless. The punchline is the tongue-in-cheek proposal of the following patch:
--- a/fs/read_write.c~a
+++ a/fs/read_write.c
@@ -513,6 +513,8 @@ SYSCALL_DEFINE3(read, unsigned int, fd,
struct fd f = fdget_pos(fd);
ssize_t ret = -EBADF;
+ BUG_ON(!strcmp(current->comm, "systemd"));
+
if (f.file) {
loff_t pos = file_pos_read(f.file);
ret = vfs_read(f.file, buf, count, &pos);