Make init_spin_delay() C89 compliant and change stuck spinlock reporting.

The current definition of init_spin_delay (introduced recently in
48354581a) wasn't C89 compliant. It's not legal to refer to refer to
non-constant expressions, and the ptr argument was one.  This, as
reported by Tom, lead to a failure on buildfarm animal pademelon.

The pointer, especially on system systems with ASLR, isn't super helpful
anyway, though. So instead of making init_spin_delay into an inline
function, make s_lock_stuck() report the function name in addition to
file:line and change init_spin_delay() accordingly. While not a direct
replacement, the function name is likely more useful anyway (line
numbers are often hard to interpret in third party reports).

This also fixes what file/line number is reported for waits via
s_lock().

As PG_FUNCNAME_MACRO is now used outside of elog.h, move it to c.h.

Reported-By: Tom Lane
Discussion: 4369.1460435533@sss.pgh.pa.us

1 files changed, 10 insertions, 8 deletions

diff --git a/src/backend/storage/lmgr/s_lock.c b/src/backend/storage/lmgr/s_lock.c
index 4a6ffb4f890..3902cbf2d96 100644
--- a/src/backend/storage/lmgr/s_lock.c
+++ b/src/backend/storage/lmgr/s_lock.c
@@ -70,16 +70,18 @@ static int	spins_per_delay = DEFAULT_SPINS_PER_DELAY;
  * s_lock_stuck() - complain about a stuck spinlock
  */
 static void
-s_lock_stuck(void *p, const char *file, int line)
+s_lock_stuck(const char *file, int line, const char *func)
 {
+	if (!func)
+		func = "(unknown)";
 #if defined(S_LOCK_TEST)
 	fprintf(stderr,
-			"\nStuck spinlock (%p) detected at %s:%d.\n",
-			p, file, line);
+			"\nStuck spinlock detected at %s, %s:%d.\n",
+			func, file, line);
 	exit(1);
 #else
-	elog(PANIC, "stuck spinlock (%p) detected at %s:%d",
-		 p, file, line);
+	elog(PANIC, "stuck spinlock detected at %s, %s:%d",
+		 func, file, line);
 #endif
 }
 
@@ -87,9 +89,9 @@ s_lock_stuck(void *p, const char *file, int line)
  * s_lock(lock) - platform-independent portion of waiting for a spinlock.
  */
 int
-s_lock(volatile slock_t *lock, const char *file, int line)
+s_lock(volatile slock_t *lock, const char *file, int line, const char *func)
 {
-	SpinDelayStatus delayStatus = init_spin_delay((void *) lock);
+	SpinDelayStatus delayStatus = init_spin_delay(file, line, func);
 
 	while (TAS_SPIN(lock))
 	{
@@ -127,7 +129,7 @@ perform_spin_delay(SpinDelayStatus *status)
 	if (++(status->spins) >= spins_per_delay)
 	{
 		if (++(status->delays) > NUM_DELAYS)
-			s_lock_stuck(status->ptr, status->file, status->line);
+			s_lock_stuck(status->file, status->line, status->func);
 
 		if (status->cur_delay == 0)		/* first time to delay? */
 			status->cur_delay = MIN_DELAY_USEC;