#!/usr/bin/perl

use strict;

my @file = <DATA>;

for my $i (0 .. $#file) {
    if ( $file[$i] =~ /pattern/ ) {
        print "$file[$_]" for ($i-3 .. $i-1);
    }
}

__DATA__
log info line yada yada 0
log info line yada yada 1
log info line yada yada 2
log info line yada yada 3
log info line (pattern) 4
log info line yada yada 5