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    SubjectRe: MM bug
    On Wed, 29 May 1996, Regis DUCHESNE wrote:

    > > You can simply crash the system by issuing "grep any_string /dev/zero".
    > > As the lines in /dev/zero have infinite length, grep tries to allocate still more
    > > memory for its line buffer until the memory is exhausted. But no out of memory
    > > message appear and the system gets frozen (interrupts work, but normal processes
    >
    > Yes, my system crashes too.
    >
    > Is this a kernel or a grep problem?
    > (i'm running gnu_grep-2.0 and pre-2.0.4)
    >

    It is sertainly not the grep problem because system can hang with other
    programs. Just write small test program which has huge BSS in it. Say,

    char a[128*1024*1024];

    main()
    {
    }

    Nothing happens to this program when it starts. Top shows it is 128M
    large. But if you insert some loop into the code which makes use of the
    huge array:

    #define LENGTH 128*1024*1024
    char a[LENGTH];

    main()
    {
    int i;
    for( i=0, i< LENGTH; i++) a[i] = '\0';
    }

    the program works some time and then stops responding and the only way
    out is to press Reset. At least, this is true for my box.

    Disclaimer: YOU ARE ON YOUR OWN IF TRY THIS.

    Good luck.
    Alexey

    ================================================================
    Alexey Yakovlev, Quantum Chemistry lab.
    Boreskov Institute of Catalysis, Russian Academy of Sciences
    pr. Lavrentieva 5, 630090 Novosibirsk, Russia
    phone: +7-(3832)-350264, fax: +7-(3832)-355766
    e-mail: jack@catalysis.nsk.su
    ================================================================



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