From ae79f46a3ee4a542731bdae8b30976729ede00e5 Mon Sep 17 00:00:00 2001
From: Thomas Schoebel-Theuer <tst@1und1.de>
Date: Thu, 18 Nov 2021 15:53:05 +0100
Subject: [PATCH] infra: defend against OOM and fork limits

---
 kernel/brick.h | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/kernel/brick.h b/kernel/brick.h
index 8116a723..ec9542db 100644
--- a/kernel/brick.h
+++ b/kernel/brick.h
@@ -702,17 +702,26 @@ typedef enum {
 	({								\
 		brick_thread_t *_thr = NULL;				\
 		int _max_retry = 3;					\
+		int _nr_retry = 0;					\
 									\
-		while (_max_retry-- > 0) {				\
+		for (;;) {						\
 			int _err;					\
 									\
 			flush_signals(current);				\
 			_thr = kthread_create(_thread_fn, _data, _fmt, ##_args); \
 			if (likely(!IS_ERR(_thr)))			\
 				break;					\
+			brick_yield();					\
 			_err = PTR_ERR(_thr);				\
-			if (_err == -EAGAIN || _err == -EINTR)		\
+			if (_err == -EAGAIN ||				\
+			    _err == -ENOMEM ||				\
+			    _err == -EINTR ||				\
+			    _max_retry-- > 0) {				\
+				brick_msleep(_nr_retry++);		\
+				if (_nr_retry > 1000)			\
+					_nr_retry = 1000;		\
 				continue;				\
+			}						\
 			BRICK_ERR("cannot create thread '%s', status = %d\n", _fmt, _err); \
 			_thr = NULL;					\
 			break;						\