[mdb-discuss] stack overflow within mdb itself

[Alexander Kolbasov]

Edward Pilatowicz <edward.pilatowicz at sun.com> wrote:

    ED> iirc, at some point, someone had a tool which could look at a kernel
    ED> panic stack trace and tell you the stack usage of each frame.  but that
    ED> is only for post mortem analysis.  afaik we don't have any way of
    ED> getting this information from the compiler, and we don't have any tools
    ED> that can do assembly analysis to determine this information.

Here is a little script that does just that:

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#! /usr/bin/perl
#
# This program is useful in dealing with stack overflows. It shows stack
# consumption by each function.
#
# Alexander Kolbasov <Alexander.Kolbasov at sun.com>
#
# The input to the script is the result of MDB $C function.
#

$stsize = 0;
$lastfunc = '';

while (<>) {
    @foo=split;
    $addr=$foo[0];
    $addr =~ s/^0+//g;
    $tmp=hex($addr);
    $func=$foo[1];
    $func =~ s/\+.*$//;
    if ($last) {
        $stsize -= $size;
        if ($size > 0) {
            printf "+%8d: %8d: %s %s\n", $stsize, $size, $lastaddr, $lastfunc;
        } else {
            printf "-%8d: %8s  %s %s\n", $stsize, "", $lastaddr, $lastfunc;
        }
        $size = $tmp - $last;
    }
    $last = $tmp;
    $lastaddr = $addr;
    $lastfunc = $func;
}

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