[sanitizer] Add diagnostics for munmap failure

We are seeing CHECK is triggered there, but it's unclear why.

Author: vitalybuka

compiler-rt/lib/sanitizer_common/sanitizer_common.cpp

@@ -61,6 +61,26 @@ void NORETURN ReportMmapFailureAndDie(uptr size, const char *mem_type,
   UNREACHABLE("unable to mmap");
 }
 
+void NORETURN ReportMunmapFailureAndDie(void *addr, uptr size, error_t err,
+                                        bool raw_report) {
+  static int recursion_count;
+  if (raw_report || recursion_count) {
+    // If raw report is requested or we went into recursion just die.  The
+    // Report() and CHECK calls below may call mmap recursively and fail.
+    RawWrite("ERROR: Failed to mmap\n");
+    Die();
+  }
+  recursion_count++;
+  Report(
+      "ERROR: %s failed to deallocate 0x%zx (%zd) bytes at address %p (error "
+      "code: %d)\n",
+      SanitizerToolName, size, size, addr, err);
+#if !SANITIZER_GO
+  DumpProcessMap();
+#endif
+  UNREACHABLE("unable to unmmap");
+}
+
 typedef bool UptrComparisonFunction(const uptr &a, const uptr &b);
 typedef bool U32ComparisonFunction(const u32 &a, const u32 &b);
 

compiler-rt/lib/sanitizer_common/sanitizer_common.h

@@ -315,6 +315,8 @@ CheckFailed(const char *file, int line, const char *cond, u64 v1, u64 v2);
 void NORETURN ReportMmapFailureAndDie(uptr size, const char *mem_type,
                                       const char *mmap_type, error_t err,
                                       bool raw_report = false);
+void NORETURN ReportMunmapFailureAndDie(void *ptr, uptr size, error_t err,
+                                        bool raw_report = false);
 
 // Returns true if the platform-specific error reported is an OOM error.
 bool ErrorIsOOM(error_t err);

compiler-rt/lib/sanitizer_common/sanitizer_posix.cpp

@@ -57,11 +57,9 @@ void *MmapOrDie(uptr size, const char *mem_type, bool raw_report) {
 void UnmapOrDie(void *addr, uptr size) {
   if (!addr || !size) return;
   uptr res = internal_munmap(addr, size);
-  if (UNLIKELY(internal_iserror(res))) {
-    Report("ERROR: %s failed to deallocate 0x%zx (%zd) bytes at address %p\n",
-           SanitizerToolName, size, size, addr);
-    CHECK("unable to unmap" && 0);
-  }
+  int reserrno;
+  if (UNLIKELY(internal_iserror(res, &reserrno)))
+    ReportMunmapFailureAndDie(addr, size, reserrno);
   DecreaseTotalMmap(size);
 }