[klibc] klibc and what's the next step?
tytso at mit.edu
Sat Jul 1 17:05:28 PDT 2006
On Sat, Jul 01, 2006 at 01:08:17PM -0700, Linus Torvalds wrote:
> The argument that user space is more debuggable has been shown to be
> largely a red herring. User space is only more debuggable if it does
> something independent, and we've seen that user space is _harder_ to debug
> than kernel space if we have events going back and forth.
In addition, userspace is debuggable only only if the initramfs has
enough debugging code in their (like a real live working shell,
strace, basic shell commands etc.) Otherwise, it becomes even more
hellish to debug. I wasted a huge amount of time trying to figure out
why the RHEL4 initramfs was incompatible with modern kernels using the
MPT Fusion SCSI driver, because I couldn't make it stop and break out
to a working shell; it had some busybox-like nash thing that wasn't
designed for user interaction, so all I could do was try to make tiny
changes to the initramfs, wait for the !@#@# very long boot cycle, and
watch the initial ramdisk fail to mount the root and crash, and
repeat, for hours on end. RHEL4's userspace root mount system was
***not*** more debuggable, not in the last. Adding printk's into a
kernel and recompiling would have been easier, and far less
Hopefully kinit will be better, but it's definitely not the case that
userpsace is easier to debug.
More information about the klibc