"my" allocates a new variable, so what you're doing is completely safe.

(Optimisations normally cause the variable to be reused, but they are specifically disabled when a reference escapes the scope like here.)

Well, the needless use of a global variable probably isn't that safe. Return the reference instead.

use strict;    # Always!
use warnings;  # Always!

B(A());

sub A {
    my @array = qw(value_1 value_2);
    return \@array;
}

sub B {
    my ($array_ref) = @_;
    foreach my $i ( @{$array_ref} ) {
        print "Array Value: $i \n";
    }
}
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