postgres.git / summary / log / commit / refs

commit    fc3f4453a2bc95549682e23600b22e658cb2d6d7
Author:   Andres Freund <andres@anarazel.de>
Date:     Mon Apr 06 01:23:30 2020 +0000

    Recompute stack base in forked postmaster children.
    
    This is for the benefit of running postgres under the rr
    debugger. When using rr signal handlers running while a syscall is
    active use an alternative stack. As e.g. bgworkers are started from
    within signal handlers, the forked backend then has a different stack
    base than postmaster. Previously that subsequently lead to those
    processes triggering spurious "stack depth limit exceeded" errors.
    
    Discussion: https://postgr.es/m/20200327182217.ubrrl32lyfhxfwk5@alap3.anarazel.de


 src/backend/postmaster/postmaster.c | 5 -----
 src/backend/utils/init/miscinit.c   | 9 +++++++++
 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 73d278f3b2c..0578e92ba9c 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -4900,11 +4900,6 @@ SubPostmasterMain(int argc, char *argv[])
 	/* Close the postmaster's sockets (as soon as we know them) */
 	ClosePostmasterPorts(strcmp(argv[1], "--forklog") == 0);
 
-	/*
-	 * 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.
diff --git a/src/backend/utils/init/miscinit.c b/src/backend/utils/init/miscinit.c
index a7b7b12249d..6fe25c023a4 100644
--- a/src/backend/utils/init/miscinit.c
+++ b/src/backend/utils/init/miscinit.c
@@ -92,6 +92,15 @@ InitPostmasterChild(void)
 {
 	IsUnderPostmaster = true;	/* we are a postmaster subprocess now */
 
+	/*
+	 * Set reference point for stack-depth checking. We re-do that even in the
+	 * !EXEC_BACKEND case, because there are some edge cases where processes
+	 * are started with an alternative stack (e.g. starting bgworkers when
+	 * running postgres using the rr debugger, as bgworkers are launched from
+	 * signal handlers).
+	 */
+	set_stack_base();
+
 	InitProcessGlobals();
 
 	/*


[parent: f946069e6827]