From 728be93977152e0be222a54e6247aa60415e60bc Mon Sep 17 00:00:00 2001
From: Daan Leijen <daan@microsoft.com>
Date: Thu, 17 Jun 2021 19:38:51 -0700
Subject: [PATCH 1/2] fix for #414 making numa node count atomic

---
 include/mimalloc-internal.h |  7 ++++---
 src/os.c                    | 20 +++++++++++++-------
 2 files changed, 17 insertions(+), 10 deletions(-)

diff --git a/include/mimalloc-internal.h b/include/mimalloc-internal.h
index 4a803ff5..1e1a7966 100644
--- a/include/mimalloc-internal.h
+++ b/include/mimalloc-internal.h
@@ -667,13 +667,14 @@ static inline uintptr_t _mi_random_shuffle(uintptr_t x) {
 int    _mi_os_numa_node_get(mi_os_tld_t* tld);
 size_t _mi_os_numa_node_count_get(void);
 
-extern size_t _mi_numa_node_count;
+extern _Atomic(size_t) _mi_numa_node_count;
 static inline int _mi_os_numa_node(mi_os_tld_t* tld) {
-  if (mi_likely(_mi_numa_node_count == 1)) return 0;
+  if (mi_likely(mi_atomic_load_relaxed(&_mi_numa_node_count) == 1)) return 0;
   else return _mi_os_numa_node_get(tld);
 }
 static inline size_t _mi_os_numa_node_count(void) {
-  if (mi_likely(_mi_numa_node_count>0)) return _mi_numa_node_count;
+  const size_t count = mi_atomic_load_relaxed(&_mi_numa_node_count);
+  if (mi_likely(count>0)) return count;
   else return _mi_os_numa_node_count_get();
 }
 
diff --git a/src/os.c b/src/os.c
index 5fed6b93..85415232 100644
--- a/src/os.c
+++ b/src/os.c
@@ -1202,17 +1202,23 @@ static size_t mi_os_numa_node_countx(void) {
 }
 #endif
 
-size_t _mi_numa_node_count = 0;   // cache the node count
+_Atomic(size_t)  _mi_numa_node_count; // = 0   // cache the node count
 
 size_t _mi_os_numa_node_count_get(void) {
-  if (mi_unlikely(_mi_numa_node_count <= 0)) {
+  size_t count = mi_atomic_load_acquire(&_mi_numa_node_count);
+  if (count <= 0) {
     long ncount = mi_option_get(mi_option_use_numa_nodes); // given explicitly?
-    if (ncount <= 0) ncount = (long)mi_os_numa_node_countx();        // or detect dynamically
-    _mi_numa_node_count = (size_t)(ncount <= 0 ? 1 : ncount);
-    _mi_verbose_message("using %zd numa regions\n", _mi_numa_node_count);
+    if (ncount > 0) {
+      count = (size_t)ncount;
+    }
+    else {
+      count = mi_os_numa_node_countx(); // or detect dynamically
+      if (count == 0) count = 1;
+    }    
+    mi_atomic_store_release(&_mi_numa_node_count, count); // save it
+    _mi_verbose_message("using %zd numa regions\n", count);
   }
-  mi_assert_internal(_mi_numa_node_count >= 1);
-  return _mi_numa_node_count;
+  return count;
 }
 
 int _mi_os_numa_node_get(mi_os_tld_t* tld) {

From 752594e76423526e108413731518a26e3322b9ca Mon Sep 17 00:00:00 2001
From: Daan Leijen <daan@microsoft.com>
Date: Thu, 17 Jun 2021 19:47:41 -0700
Subject: [PATCH 2/2] add test for #414

---
 test/main-override.cpp | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/test/main-override.cpp b/test/main-override.cpp
index 890b79a6..5fe3f9a3 100644
--- a/test/main-override.cpp
+++ b/test/main-override.cpp
@@ -33,6 +33,7 @@ void padding_shrink();         // issue #209
 void various_tests();
 void test_mt_shutdown();
 void fail_aslr();              // issue #372
+void tsan_numa_test();         // issue #414
 
 int main() {
   mi_stats_reset();  // ignore earlier allocations
@@ -41,6 +42,8 @@ int main() {
   heap_late_free();
   padding_shrink();
   various_tests();
+  tsan_numa_test();
+
   //test_mt_shutdown();
   //fail_aslr();
   mi_stats_print(NULL);
@@ -216,4 +219,16 @@ void fail_aslr() {
   void* p = malloc(sz);
   printf("pointer p: %p: area up to %p\n", p, (uint8_t*)p + sz);
   *(int*)0x5FFFFFFF000 = 0;  // should segfault
+}
+
+// issues #414
+void dummy_worker() {
+  void* p = mi_malloc(0);
+  mi_free(p);  
+}
+
+void tsan_numa_test() {
+  auto t1 = std::thread(dummy_worker);
+  dummy_worker();
+  t1.join();
 }
\ No newline at end of file