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    DateSat, 1 Jul 2006 20:05:28 -0400
    FromTheodore Tso <>
    SubjectRe: [klibc] klibc and what's the next step?
    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.
    
    Agreed, 100%.
    
    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
    frustrating.
    
    Hopefully kinit will be better, but it's definitely not the case that
    userpsace is easier to debug.  
    
    						- Ted
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