diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index 19ba26b914..2cef56f115 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -454,8 +454,8 @@ AutoVacLauncherMain(int argc, char *argv[])
 	pqsignal(SIGHUP, SignalHandlerForConfigReload);
 	pqsignal(SIGINT, StatementCancelHandler);
 	pqsignal(SIGTERM, SignalHandlerForShutdownRequest);
+	/* SIGQUIT handler was already set up by InitPostmasterChild */
 
-	pqsignal(SIGQUIT, quickdie);
 	InitializeTimeouts();		/* establishes SIGALRM handler */
 
 	pqsignal(SIGPIPE, SIG_IGN);
@@ -498,9 +498,10 @@ AutoVacLauncherMain(int argc, char *argv[])
 	 *
 	 * Note that we use sigsetjmp(..., 1), so that the prevailing signal mask
 	 * (to wit, BlockSig) will be restored when longjmp'ing to here.  Thus,
-	 * signals will be blocked until we complete error recovery.  It might
-	 * seem that this policy makes the HOLD_INTERRUPTS() call redundant, but
-	 * it is not since InterruptPending might be set already.
+	 * signals other than SIGQUIT will be blocked until we complete error
+	 * recovery.  It might seem that this policy makes the HOLD_INTERRUPTS()
+	 * call redundant, but it is not since InterruptPending might be set
+	 * already.
 	 */
 	if (sigsetjmp(local_sigjmp_buf, 1) != 0)
 	{
@@ -1531,7 +1532,8 @@ AutoVacWorkerMain(int argc, char *argv[])
 	 */
 	pqsignal(SIGINT, StatementCancelHandler);
 	pqsignal(SIGTERM, die);
-	pqsignal(SIGQUIT, quickdie);
+	/* SIGQUIT handler was already set up by InitPostmasterChild */
+
 	InitializeTimeouts();		/* establishes SIGALRM handler */
 
 	pqsignal(SIGPIPE, SIG_IGN);
@@ -1562,9 +1564,9 @@ AutoVacWorkerMain(int argc, char *argv[])
 	 *
 	 * Note that we use sigsetjmp(..., 1), so that the prevailing signal mask
 	 * (to wit, BlockSig) will be restored when longjmp'ing to here.  Thus,
-	 * signals will be blocked until we exit.  It might seem that this policy
-	 * makes the HOLD_INTERRUPTS() call redundant, but it is not since
-	 * InterruptPending might be set already.
+	 * signals other than SIGQUIT will be blocked until we exit.  It might
+	 * seem that this policy makes the HOLD_INTERRUPTS() call redundant, but
+	 * it is not since InterruptPending might be set already.
 	 */
 	if (sigsetjmp(local_sigjmp_buf, 1) != 0)
 	{
diff --git a/src/backend/postmaster/bgworker.c b/src/backend/postmaster/bgworker.c
index d043ced686..5a9a0e3435 100644
--- a/src/backend/postmaster/bgworker.c
+++ b/src/backend/postmaster/bgworker.c
@@ -731,9 +731,9 @@ StartBackgroundWorker(void)
 		pqsignal(SIGFPE, SIG_IGN);
 	}
 	pqsignal(SIGTERM, bgworker_die);
+	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGHUP, SIG_IGN);
 
-	pqsignal(SIGQUIT, SignalHandlerForCrashExit);
 	InitializeTimeouts();		/* establishes SIGALRM handler */
 
 	pqsignal(SIGPIPE, SIG_IGN);
diff --git a/src/backend/postmaster/bgwriter.c b/src/backend/postmaster/bgwriter.c
index c96568149f..a7afa758b6 100644
--- a/src/backend/postmaster/bgwriter.c
+++ b/src/backend/postmaster/bgwriter.c
@@ -104,7 +104,7 @@ BackgroundWriterMain(void)
 	pqsignal(SIGHUP, SignalHandlerForConfigReload);
 	pqsignal(SIGINT, SIG_IGN);
 	pqsignal(SIGTERM, SignalHandlerForShutdownRequest);
-	pqsignal(SIGQUIT, SignalHandlerForCrashExit);
+	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
 	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
@@ -115,10 +115,6 @@ BackgroundWriterMain(void)
 	 */
 	pqsignal(SIGCHLD, SIG_DFL);
 
-	/* We allow SIGQUIT (SignalHandlerForCrashExit) at all times */
-	sigdelset(&BlockSig, SIGQUIT);
-	PG_SETMASK(&BlockSig);
-
 	/*
 	 * We just started, assume there has been either a shutdown or
 	 * end-of-recovery snapshot.
diff --git a/src/backend/postmaster/checkpointer.c b/src/backend/postmaster/checkpointer.c
index 45f5deca72..3e7dcd4f76 100644
--- a/src/backend/postmaster/checkpointer.c
+++ b/src/backend/postmaster/checkpointer.c
@@ -198,7 +198,7 @@ CheckpointerMain(void)
 	pqsignal(SIGHUP, SignalHandlerForConfigReload);
 	pqsignal(SIGINT, ReqCheckpointHandler); /* request checkpoint */
 	pqsignal(SIGTERM, SIG_IGN); /* ignore SIGTERM */
-	pqsignal(SIGQUIT, SignalHandlerForCrashExit);
+	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
 	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
@@ -209,10 +209,6 @@ CheckpointerMain(void)
 	 */
 	pqsignal(SIGCHLD, SIG_DFL);
 
-	/* We allow SIGQUIT (SignalHandlerForCrashExit) at all times */
-	sigdelset(&BlockSig, SIGQUIT);
-	PG_SETMASK(&BlockSig);
-
 	/*
 	 * Initialize so that first time-driven event happens at the correct time.
 	 */
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index 37be0e2bbb..ed1b65358d 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -228,7 +228,7 @@ PgArchiverMain(int argc, char *argv[])
 	pqsignal(SIGHUP, SignalHandlerForConfigReload);
 	pqsignal(SIGINT, SIG_IGN);
 	pqsignal(SIGTERM, SignalHandlerForShutdownRequest);
-	pqsignal(SIGQUIT, SignalHandlerForCrashExit);
+	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
 	pqsignal(SIGUSR1, pgarch_waken);
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 3cd6fa30eb..959e3b8873 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -4355,7 +4355,7 @@ BackendInitialize(Port *port)
 	 * cleaned up.
 	 */
 	pqsignal(SIGTERM, process_startup_packet_die);
-	pqsignal(SIGQUIT, SignalHandlerForCrashExit);
+	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	InitializeTimeouts();		/* establishes SIGALRM handler */
 	PG_SETMASK(&StartupBlockSig);
 
@@ -4435,7 +4435,7 @@ BackendInitialize(Port *port)
 	status = ProcessStartupPacket(port, false, false);
 
 	/*
-	 * Disable the timeout, and prevent SIGTERM/SIGQUIT again.
+	 * Disable the timeout, and prevent SIGTERM again.
 	 */
 	disable_timeout(STARTUP_PACKET_TIMEOUT, false);
 	PG_SETMASK(&BlockSig);
@@ -4983,10 +4983,6 @@ SubPostmasterMain(int argc, char *argv[])
 	if (strcmp(argv[1], "--forkavworker") == 0)
 		AutovacuumWorkerIAm();
 
-	/* In EXEC_BACKEND case we will not have inherited these settings */
-	pqinitmask();
-	PG_SETMASK(&BlockSig);
-
 	/* Read in remaining GUC variables */
 	read_nondefault_variables();
 
diff --git a/src/backend/postmaster/startup.c b/src/backend/postmaster/startup.c
index fd9ac35dac..64af7b8707 100644
--- a/src/backend/postmaster/startup.c
+++ b/src/backend/postmaster/startup.c
@@ -175,7 +175,7 @@ StartupProcessMain(void)
 	pqsignal(SIGHUP, StartupProcSigHupHandler); /* reload config file */
 	pqsignal(SIGINT, SIG_IGN);	/* ignore query cancel */
 	pqsignal(SIGTERM, StartupProcShutdownHandler);	/* request shutdown */
-	pqsignal(SIGQUIT, SignalHandlerForCrashExit);
+	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	InitializeTimeouts();		/* establishes SIGALRM handler */
 	pqsignal(SIGPIPE, SIG_IGN);
 	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
diff --git a/src/backend/postmaster/walwriter.c b/src/backend/postmaster/walwriter.c
index 358c0916ac..a52832fe90 100644
--- a/src/backend/postmaster/walwriter.c
+++ b/src/backend/postmaster/walwriter.c
@@ -101,7 +101,7 @@ WalWriterMain(void)
 	pqsignal(SIGHUP, SignalHandlerForConfigReload);
 	pqsignal(SIGINT, SignalHandlerForShutdownRequest);
 	pqsignal(SIGTERM, SignalHandlerForShutdownRequest);
-	pqsignal(SIGQUIT, SignalHandlerForCrashExit);
+	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
 	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
@@ -112,10 +112,6 @@ WalWriterMain(void)
 	 */
 	pqsignal(SIGCHLD, SIG_DFL);
 
-	/* We allow SIGQUIT (SignalHandlerForCrashExit) at all times */
-	sigdelset(&BlockSig, SIGQUIT);
-	PG_SETMASK(&BlockSig);
-
 	/*
 	 * Create a memory context that we will do all our work in.  We do this so
 	 * that we can reset the context during error recovery and thereby avoid
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index b180598507..17f1a49f87 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -270,7 +270,7 @@ WalReceiverMain(void)
 	pqsignal(SIGHUP, WalRcvSigHupHandler);	/* set flag to read config file */
 	pqsignal(SIGINT, SIG_IGN);
 	pqsignal(SIGTERM, WalRcvShutdownHandler);	/* request shutdown */
-	pqsignal(SIGQUIT, SignalHandlerForCrashExit);
+	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	pqsignal(SIGALRM, SIG_IGN);
 	pqsignal(SIGPIPE, SIG_IGN);
 	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
@@ -279,10 +279,6 @@ WalReceiverMain(void)
 	/* Reset some signals that are accepted by postmaster but not here */
 	pqsignal(SIGCHLD, SIG_DFL);
 
-	/* We allow SIGQUIT (SignalHandlerForCrashExit) at all times */
-	sigdelset(&BlockSig, SIGQUIT);
-	PG_SETMASK(&BlockSig);
-
 	/* Load the libpq-specific functions */
 	load_file("libpqwalreceiver", false);
 	if (WalReceiverFunctions == NULL)
diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c
index 3f756b470a..5e6ae6fde5 100644
--- a/src/backend/replication/walsender.c
+++ b/src/backend/replication/walsender.c
@@ -3035,7 +3035,7 @@ WalSndSignals(void)
 	pqsignal(SIGHUP, SignalHandlerForConfigReload);
 	pqsignal(SIGINT, StatementCancelHandler);	/* query cancel */
 	pqsignal(SIGTERM, die);		/* request shutdown */
-	pqsignal(SIGQUIT, quickdie);	/* hard crash time */
+	/* SIGQUIT handler was already set up by InitPostmasterChild */
 	InitializeTimeouts();		/* establishes SIGALRM handler */
 	pqsignal(SIGPIPE, SIG_IGN);
 	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index c9424f167c..411cfadbff 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -3820,7 +3820,8 @@ PostgresMain(int argc, char *argv[],
 	}
 
 	/*
-	 * Set up signal handlers and masks.
+	 * Set up signal handlers.  (InitPostmasterChild or InitStandaloneProcess
+	 * has already set up BlockSig and made that the active signal mask.)
 	 *
 	 * Note that postmaster blocked all signals before forking child process,
 	 * so there is no race condition whereby we might receive a signal before
@@ -3842,6 +3843,9 @@ PostgresMain(int argc, char *argv[],
 		pqsignal(SIGTERM, die); /* cancel current query and exit */
 
 		/*
+		 * In a postmaster child backend, replace SignalHandlerForCrashExit
+		 * with quickdie, so we can tell the client we're dying.
+		 *
 		 * In a standalone backend, SIGQUIT can be generated from the keyboard
 		 * easily, while SIGTERM cannot, so we make both signals do die()
 		 * rather than quickdie().
@@ -3871,16 +3875,6 @@ PostgresMain(int argc, char *argv[],
 									 * platforms */
 	}
 
-	pqinitmask();
-
-	if (IsUnderPostmaster)
-	{
-		/* We allow SIGQUIT (quickdie) at all times */
-		sigdelset(&BlockSig, SIGQUIT);
-	}
-
-	PG_SETMASK(&BlockSig);		/* block everything except SIGQUIT */
-
 	if (!IsUnderPostmaster)
 	{
 		/*
diff --git a/src/backend/utils/init/miscinit.c b/src/backend/utils/init/miscinit.c
index cf8f9579c3..ed2ab4b5b2 100644
--- a/src/backend/utils/init/miscinit.c
+++ b/src/backend/utils/init/miscinit.c
@@ -32,10 +32,12 @@
 #include "catalog/pg_authid.h"
 #include "common/file_perm.h"
 #include "libpq/libpq.h"
+#include "libpq/pqsignal.h"
 #include "mb/pg_wchar.h"
 #include "miscadmin.h"
 #include "pgstat.h"
 #include "postmaster/autovacuum.h"
+#include "postmaster/interrupt.h"
 #include "postmaster/postmaster.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
@@ -133,6 +135,23 @@ InitPostmasterChild(void)
 		elog(FATAL, "setsid() failed: %m");
 #endif
 
+	/* In EXEC_BACKEND case we will not have inherited BlockSig etc values */
+#ifdef EXEC_BACKEND
+	pqinitmask();
+#endif
+
+	/*
+	 * Every postmaster child process is expected to respond promptly to
+	 * SIGQUIT at all times.  Therefore we centrally remove SIGQUIT from
+	 * BlockSig and install a suitable signal handler.  (Client-facing
+	 * processes may choose to replace this default choice of handler with
+	 * quickdie().)  All other blockable signals remain blocked for now.
+	 */
+	pqsignal(SIGQUIT, SignalHandlerForCrashExit);
+
+	sigdelset(&BlockSig, SIGQUIT);
+	PG_SETMASK(&BlockSig);
+
 	/* Request a signal if the postmaster dies, if possible. */
 	PostmasterDeathSignalInit();
 }
@@ -155,6 +174,13 @@ InitStandaloneProcess(const char *argv0)
 	InitLatch(MyLatch);
 	InitializeLatchWaitSet();
 
+	/*
+	 * For consistency with InitPostmasterChild, initialize signal mask here.
+	 * But we don't unblock SIGQUIT or provide a default handler for it.
+	 */
+	pqinitmask();
+	PG_SETMASK(&BlockSig);
+
 	/* Compute paths, no postmaster to inherit from */
 	if (my_exec_path[0] == '\0')
 	{