From: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Date: Sun, 27 Sep 2020 23:45:50 +0000 (-0400)
Subject: pan/bi: Fix memory corruption in scheduler
X-Git-Tag: upstream/21.0.0~4417
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=405544eae56e06845e026b73527016db1638ff45;p=platform%2Fupstream%2Fmesa.git

pan/bi: Fix memory corruption in scheduler

If empty the last will be bogus, I think. Missing Rust hard right around
now.

Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7081>
---

diff --git a/src/panfrost/bifrost/bi_schedule.c b/src/panfrost/bifrost/bi_schedule.c
index 2ff1d50..a336e5e 100644
--- a/src/panfrost/bifrost/bi_schedule.c
+++ b/src/panfrost/bifrost/bi_schedule.c
@@ -241,10 +241,11 @@ bi_schedule(bi_context *ctx)
 
                 /* Back-to-back bit affects only the last clause of a block,
                  * the rest are implicitly true */
-                bi_clause *last_clause = list_last_entry(&bblock->clauses, bi_clause, link);
 
-                if (last_clause)
+                if (!list_is_empty(&bblock->clauses)) {
+                        bi_clause *last_clause = list_last_entry(&bblock->clauses, bi_clause, link);
                         last_clause->back_to_back = bi_back_to_back(bblock);
+                }
 
                 bblock->scheduled = true;
         }