Do stack-depth checking in all postmaster children.

We used to only initialize the stack base pointer when starting up a regular
backend, not in other processes. In particular, autovacuum workers can run
arbitrary user code, and without stack-depth checking, infinite recursion
in e.g an index expression will bring down the whole cluster.

The comment about PL/Java using set_stack_base() is not yet true. As the
code stands, PL/java still modifies the stack_base_ptr variable directly.
However, it's been discussed in the PL/Java mailing list that it should be
changed to use the function, because PL/Java is currently oblivious to the
register stack used on Itanium. There's another issues with PL/Java, namely
that the stack base pointer it sets is not really the base of the stack, it
could be something close to the bottom of the stack. That's a separate issue
that might need some further changes to this code, but that's a different
story.

Backpatch to all supported releases.

1 files changed, 13 insertions, 0 deletions

diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 610cb5907e5..b186eed8f47 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -246,6 +246,19 @@ extern bool VacuumCostActive;
 
 
 /* in tcop/postgres.c */
+
+#if defined(__ia64__) || defined(__ia64)
+typedef struct
+{
+	char	   *stack_base_ptr;
+	char	   *register_stack_base_ptr;
+} pg_stack_base_t;
+#else
+typedef char *pg_stack_base_t;
+#endif
+
+extern pg_stack_base_t set_stack_base(void);
+extern void restore_stack_base(pg_stack_base_t base);
 extern void check_stack_depth(void);
 
 /* in tcop/utility.c */