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, 10 insertions, 0 deletions

diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 1dac6954885..a481eef2c28 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -971,6 +971,11 @@ PostmasterMain(int argc, char *argv[])
 	set_max_safe_fds();
 
 	/*
+	 * Set reference point for stack-depth checking.
+	 */
+	set_stack_base();
+
+	/*
 	 * Initialize the list of active backends.
 	 */
 	BackendList = DLNewList();
@@ -3978,6 +3983,11 @@ SubPostmasterMain(int argc, char *argv[])
 	read_backend_variables(argv[2], &port);
 
 	/*
+	 * Set reference point for stack-depth checking
+	 */
+	set_stack_base();
+
+	/*
 	 * Set up memory area for GSS information. Mirrors the code in ConnCreate
 	 * for the non-exec case.
 	 */