Re: Memory leak

[Aharon Robbins]

Hi.  Re this:

Aleksey Cheusov <address@hidden> wrote:

> The following test programs shows that there is a memory leak somewhere
> in GAWK.
>
>    #!/usr/bin/gawk -f
>
>    BEGIN {
>       val_hash1 [1] = 1
>
> #     for (j=1; j<=100000000; j++) {
>       for (j=1; j<=1000000; j++) {
>          test2( val_hash1 )
>       }
>    }
>
>    function test2 (ValHash1,                       i)
>    {
>       for (i in ValHash1) {
>          return # *** #
>       }
>    }
>
> This program fails like this.
>
>    0 cheusov>gawk -f ~/tmp/2.awk 
>    gawk: /home/cheusov/tmp/2.awk:16: fatal: push_forloop: loop_stack: can't 
> allocate 25165824 bytes of memory (Cannot allocate memory)
>    2 cheusov>
>
> After changing 'return' statement marked as '# *** #' to 'break',
> everything works fine.
>
> The problem is reproducinble under NetBSD and Linux.
> -- 
> Best regards, Aleksey Cheusov.

This is indeed a bug.  Here is a patch. It will shortly make its way
into the CVS version.

Thanks for reporting this,

Arnold
---------------------------------------------------

--- ../gawk-3.1.6/eval.c        2007-08-11 22:39:49.000000000 +0300
+++ eval.c      2009-04-16 20:58:04.000000000 +0300
@@ -1789,6 +1789,7 @@
        int volatile save_loop_tag_valid = FALSE;
        NODE *save_ret_node;
        extern NODE *ret_node;
+       size_t current_nloops_active = 0;
 
        /* tree->rnode is a Node_val giving function name */
        /* tree->lnode is Node_expression_list of calling args. */
@@ -1831,12 +1832,16 @@
                loop_tag_valid = FALSE;
        }
        PUSH_BINDING(func_tag_stack, func_tag, func_tag_valid);
+       current_nloops_active = nloops_active;
        save_ret_node = ret_node;
        ret_node = Nnull_string;        /* default return value */
        INCREMENT(f->exec_count);       /* count function calls */
        if (setjmp(func_tag) == 0)
                (void) interpret(f->rnode);
 
+       while (nloops_active > current_nloops_active)
+               pop_forloop();
+
        r = ret_node;
        ret_node = (NODE *) save_ret_node;
        RESTORE_BINDING(func_tag_stack, func_tag, func_tag_valid);