From 2d5b708ff6222775aed3dca87ac094aedc0b7571 Mon Sep 17 00:00:00 2001
From: Thomas Schoebel-Theuer <mars@asus>
Date: Wed, 15 Jun 2022 21:44:57 +0200
Subject: [PATCH] copy: safeguard advance on concluded states

---
 kernel/mars_copy.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/kernel/mars_copy.c b/kernel/mars_copy.c
index 427d518e..d1079fcb 100644
--- a/kernel/mars_copy.c
+++ b/kernel/mars_copy.c
@@ -846,6 +846,7 @@ int _run_copy(struct copy_brick *brick, loff_t this_start)
 			unsigned len;
 			unsigned index = GET_INDEX(pos);
 			struct copy_state *st = &GET_STATE(brick, index);
+			bool is_active;
 
 			if (st->state != COPY_STATE_FINISHED) {
 				break;
@@ -870,6 +871,16 @@ int _run_copy(struct copy_brick *brick, loff_t this_start)
 				}
 				break;
 			}
+			is_active =
+				(READ_ONCE(st->active[0]) |
+				 READ_ONCE(st->active[1])) != 0;
+			if (is_active) {
+				break;
+			}
+			if (READ_ONCE(st->table[0]) ||
+			    READ_ONCE(st->table[1])) {
+				break;
+			}
 			// rollover
 			st->state = COPY_STATE_START;
 			len = st->len;