From bf9c3bd08847e7dc1972db52b419b21171bc6c6e Mon Sep 17 00:00:00 2001
From: Igor Kostenko <isanych@gmail.com>
Date: Mon, 14 Sep 2020 10:50:22 +0100
Subject: [PATCH 1/2] Fix rare access violation on out of memory

---
 src/region.c  | 8 ++++++--
 src/segment.c | 9 ++++++++-
 2 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/src/region.c b/src/region.c
index bebc29fd..fa51c298 100644
--- a/src/region.c
+++ b/src/region.c
@@ -297,9 +297,13 @@ static void* mi_region_try_alloc(size_t blocks, bool* commit, bool* is_large, bo
     mi_bitmap_claim(&region->commit, 1, blocks, bit_idx, &any_uncommitted);
     if (any_uncommitted) {
       mi_assert_internal(!info.x.is_large);
-      bool commit_zero;
-      _mi_mem_commit(p, blocks * MI_SEGMENT_SIZE, &commit_zero, tld);
+      bool commit_zero = false;
+      bool ok = _mi_mem_commit(p, blocks * MI_SEGMENT_SIZE, &commit_zero, tld);
       if (commit_zero) *is_zero = true;
+      if (!ok)
+      {
+        return NULL;
+      }
     }
   }
   else {
diff --git a/src/segment.c b/src/segment.c
index a5077711..35fc3ba7 100644
--- a/src/segment.c
+++ b/src/segment.c
@@ -208,7 +208,11 @@ static void mi_segment_protect(mi_segment_t* segment, bool protect, mi_os_tld_t*
       uint8_t* start = (uint8_t*)segment + segment->segment_size - os_psize;
       if (protect && !segment->mem_is_committed) {
         // ensure secure page is committed
+#if (MI_DEBUG>1)
+        bool ok =
+#endif
         _mi_mem_commit(start, os_psize, NULL, tld);
+        mi_assert_internal(ok);
       }
       mi_segment_protect_range(start, os_psize, protect);
     }
@@ -606,8 +610,11 @@ static mi_segment_t* mi_segment_init(mi_segment_t* segment, size_t required, mi_
       // ensure the initial info is committed
       if (segment->capacity < capacity) {
         bool commit_zero = false;
-        _mi_mem_commit(segment, pre_size, &commit_zero, tld->os);
+        bool ok = _mi_mem_commit(segment, pre_size, &commit_zero, tld->os);
         if (commit_zero) is_zero = true;
+        if (!ok) {
+          return NULL;
+        }
       }
     }
   }

From 840eba28742b324d45b09e44e351767de29a8ced Mon Sep 17 00:00:00 2001
From: daan <daanl@outlook.com>
Date: Mon, 14 Sep 2020 09:02:06 -0700
Subject: [PATCH 2/2] improve handling of out-of-memory situations

---
 src/region.c  |  8 ++++----
 src/segment.c | 16 +++++++++-------
 2 files changed, 13 insertions(+), 11 deletions(-)

diff --git a/src/region.c b/src/region.c
index fa51c298..aa4f95b5 100644
--- a/src/region.c
+++ b/src/region.c
@@ -298,12 +298,12 @@ static void* mi_region_try_alloc(size_t blocks, bool* commit, bool* is_large, bo
     if (any_uncommitted) {
       mi_assert_internal(!info.x.is_large);
       bool commit_zero = false;
-      bool ok = _mi_mem_commit(p, blocks * MI_SEGMENT_SIZE, &commit_zero, tld);
-      if (commit_zero) *is_zero = true;
-      if (!ok)
-      {
+      if (!_mi_mem_commit(p, blocks * MI_SEGMENT_SIZE, &commit_zero, tld)) {
+        // failed to commit! unclaim and return
+        mi_bitmap_unclaim(&region->in_use, 1, blocks, bit_idx);
         return NULL;
       }
+      if (commit_zero) *is_zero = true;      
     }
   }
   else {
diff --git a/src/segment.c b/src/segment.c
index 35fc3ba7..0daf8ddb 100644
--- a/src/segment.c
+++ b/src/segment.c
@@ -207,14 +207,16 @@ static void mi_segment_protect(mi_segment_t* segment, bool protect, mi_os_tld_t*
       mi_assert_internal(MI_SECURE <= 1 || segment->page_kind >= MI_PAGE_LARGE);
       uint8_t* start = (uint8_t*)segment + segment->segment_size - os_psize;
       if (protect && !segment->mem_is_committed) {
-        // ensure secure page is committed
-#if (MI_DEBUG>1)
-        bool ok =
-#endif
-        _mi_mem_commit(start, os_psize, NULL, tld);
-        mi_assert_internal(ok);
+        if (protect) {
+          // ensure secure page is committed
+          if (_mi_mem_commit(start, os_psize, NULL, tld)) {  // if this fails that is ok (as it is an unaccessible page)
+            mi_segment_protect_range(start, os_psize, protect);
+          }
+        }
+      }
+      else {
+        mi_segment_protect_range(start, os_psize, protect);
       }
-      mi_segment_protect_range(start, os_psize, protect);
     }
     else {
       // or protect every page