[PATCH] Possible arithmetic with NULL pointer or test "stack_base_ptr != NULL" is irrelevant.

[Ranier Vilela]

Hi,
Of course, I don't know if it's the best solution, but it's the most obvious.
Or the test at line 3326 is irrelavant.

\backend\tcop\postgres.c
        if (stack_depth > max_stack_depth_bytes &&
                stack_base_ptr != NULL)
                return true;

Otherwise, if is relevant, substraction with NULL pointer is 
technically,undefined behavior..

Best regards.
Ranier Vilela

--- \dll\postgresql\a\backend\tcop\postgres.c   2019-11-23 13:19:20.000000000 
-0300
+++ postgres.c  2019-11-24 11:13:34.131437500 -0300
@@ -3303,7 +3303,10 @@
        /*
         * Compute distance from reference point to my local variables
         */
-       stack_depth = (long) (stack_base_ptr - &stack_top_loc);
+       if (stack_base_ptr != NULL)
+           stack_depth = (long) (stack_base_ptr - &stack_top_loc);
+       else
+           stack_depth = (long) &stack_top_loc;
 
        /*
         * Take abs value, since stacks grow up on some machines, down on others

postgres.c.patch
Description: postgres.c.patch