From: Ivan Maidanski <ivmai@mail.ru>
Date: Sat, 10 Dec 2016 07:14:39 +0000 (+0300)
Subject: Fix assertion in GC_steal_mark_stack for non-heap regions
X-Git-Tag: v7.4.6~184
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=8f35a9ee81cffc01f1fe93bea6b4e00c4495058b;p=gc

Fix assertion in GC_steal_mark_stack for non-heap regions
(similar to commit da2fcda)

* mark.c (GC_steal_mark_stack): Replace top->mse_descr.w with descr
in assertion; relax assertion condition for descr (length-containing
mse_descr.w could be larger than the current GC heap size if
mse_start points to a region in a stack or a program data root;
e.g. it could happen if MemorySanitizer is used).
---

diff --git a/mark.c b/mark.c
index 00381188..1003c76f 100644
--- a/mark.c
+++ b/mark.c
@@ -936,9 +936,13 @@ STATIC mse * GC_steal_mark_stack(mse * low, mse * high, mse * local,
             ++top;
             top -> mse_descr.w = descr;
             top -> mse_start = p -> mse_start;
-            GC_ASSERT((top->mse_descr.w & GC_DS_TAGS) != GC_DS_LENGTH ||
-                      top->mse_descr.w < (word)GC_greatest_plausible_heap_addr
-                                         - (word)GC_least_plausible_heap_addr);
+            GC_ASSERT((descr & GC_DS_TAGS) != GC_DS_LENGTH
+                      || descr < (word)GC_greatest_plausible_heap_addr
+                                        - (word)GC_least_plausible_heap_addr
+                      || (word)(p->mse_start + descr)
+                            <= (word)GC_least_plausible_heap_addr
+                      || (word)p->mse_start
+                            >= (word)GC_greatest_plausible_heap_addr);
             /* If this is a big object, count it as                     */
             /* size/256 + 1 objects.                                    */
             ++i;