Re: Linux inode.i_count overflow

From: David LeBlanc (dleblancat_private)
Date: Wed Jan 14 1998 - 13:42:14 PST

  • Next message: Casper Dik: "Re: Linux inode.i_count overflow"

    At 05:49 PM 1/14/98 +0000, Alan Cox wrote:
    
    >>    typical Linux configuration. Although you can avoid users to eat
    >>    resources this way by setting resource limits properly this effect can
    >>    be considered to be a Linux bug. Linux is protected to avoid
    >>    allocating all process slots by normal users. There are reserved
    >>    MIN_TASKS_LEFT_FOR_ROOT slots for root. So there should be also
    >>    protection to avoid allocating all memory by normal users.
    
    >This seems to be a generic Unix bug. I brought down our SGI with that
    >program, and netbsd also seems to jam solid. The general vulnerability
    >is going to be the same on all OS's (anyone got an NT port ?) or want
    >to make a summary table.
    
    So far as I know, you'll never run NT out of proc table space, since the
    limit on nearly every sort of handle under NT is 2^32.  You'll cripple it
    from RAM usage long before you run into problems with that.  The same deal
    with handles, except I think that one is only 2^32 per _process_.  Don't
    think we'll see that turn into much of an issue.  4 billion handles ought
    to be enough for anyone <g>
    
    Where you can screw up NT is that the OS has no way to limit any given
    user's RAM consumption.  So a very simple while(ptr = malloc(somesize));
    ought to bring just about any NT box close to it's knees.  This sort of
    nonsense is, however, fixed in NT 5.0.  I have inadvertantly done this to
    myself a few times, and it is somewhat interesting - NT gets very, very
    slow and quite annoyed.  It will continue running, and under some
    conditions will get irate and kill the offending process.  In fact, I did
    this last night on my work machine - came in this morning, logged in, noted
    that my app had consumed about 1/4 gig of page+RAM, killed the app and went
    about my work.
    
    
    David LeBlanc           |Why would you want to have your desktop user,
    dleblancat_private |your mere mortals, messing around with a 32-bit
                            |minicomputer-class computing environment?
                            |Scott McNealy
    



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