8292071: NMT: move MallocHeader to its own header and inline header checks

Reviewed-by: mbaesken, lucy, iklam

src/hotspot/share/services/mallocHeader.inline.hpp

@@ -0,0 +1,131 @@
+/*
+ * Copyright (c) 2014, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2021, 2022 SAP SE. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#ifndef SHARE_SERVICES_MALLOCHEADER_INLINE_HPP
+#define SHARE_SERVICES_MALLOCHEADER_INLINE_HPP
+
+#include "services/mallocHeader.hpp"
+
+#include "jvm_io.h"
+#include "utilities/debug.hpp"
+#include "utilities/globalDefinitions.hpp"
+#include "utilities/macros.hpp"
+#include "utilities/nativeCallStack.hpp"
+
+inline MallocHeader::MallocHeader(size_t size, MEMFLAGS flags, const NativeCallStack& stack, uint32_t mst_marker)
+  : _size(size), _mst_marker(mst_marker), _flags(NMTUtil::flag_to_index(flags)),
+    _unused(0), _canary(_header_canary_life_mark)
+{
+  assert(size < max_reasonable_malloc_size, "Too large allocation size?");
+  // On 32-bit we have some bits more, use them for a second canary
+  // guarding the start of the header.
+  NOT_LP64(_alt_canary = _header_alt_canary_life_mark;)
+  set_footer(_footer_canary_life_mark); // set after initializing _size
+}
+
+inline void MallocHeader::mark_block_as_dead() {
+  _canary = _header_canary_dead_mark;
+  NOT_LP64(_alt_canary = _header_alt_canary_dead_mark);
+  set_footer(_footer_canary_dead_mark);
+}
+
+inline void MallocHeader::assert_block_integrity() const {
+  char msg[256];
+  address corruption = NULL;
+  if (!check_block_integrity(msg, sizeof(msg), &corruption)) {
+    if (corruption != NULL) {
+      print_block_on_error(tty, (address)this);
+    }
+    fatal("NMT corruption: Block at " PTR_FORMAT ": %s", p2i(this), msg);
+  }
+}
+
+inline bool MallocHeader::check_block_integrity(char* msg, size_t msglen, address* p_corruption) const {
+  // Note: if you modify the error messages here, make sure you
+  // adapt the associated gtests too.
+
+  // Weed out obviously wrong block addresses of NULL or very low
+  // values. Note that we should not call this for ::free(NULL),
+  // which should be handled by os::free() above us.
+  if (((size_t)p2i(this)) < K) {
+    jio_snprintf(msg, msglen, "invalid block address");
+    return false;
+  }
+
+  // From here on we assume the block pointer to be valid. We could
+  // use SafeFetch but since this is a hot path we don't. If we are
+  // wrong, we will crash when accessing the canary, which hopefully
+  // generates distinct crash report.
+
+  // Weed out obviously unaligned addresses. NMT blocks, being the result of
+  // malloc calls, should adhere to malloc() alignment. Malloc alignment is
+  // specified by the standard by this requirement:
+  // "malloc returns a pointer which is suitably aligned for any built-in type"
+  // For us it means that it is *at least* 64-bit on all of our 32-bit and
+  // 64-bit platforms since we have native 64-bit types. It very probably is
+  // larger than that, since there exist scalar types larger than 64bit. Here,
+  // we test the smallest alignment we know.
+  // Should we ever start using std::max_align_t, this would be one place to
+  // fix up.
+  if (!is_aligned(this, sizeof(uint64_t))) {
+    *p_corruption = (address)this;
+    jio_snprintf(msg, msglen, "block address is unaligned");
+    return false;
+  }
+
+  // Check header canary
+  if (_canary != _header_canary_life_mark) {
+    *p_corruption = (address)this;
+    jio_snprintf(msg, msglen, "header canary broken");
+    return false;
+  }
+
+#ifndef _LP64
+  // On 32-bit we have a second canary, check that one too.
+  if (_alt_canary != _header_alt_canary_life_mark) {
+    *p_corruption = (address)this;
+    jio_snprintf(msg, msglen, "header canary broken");
+    return false;
+  }
+#endif
+
+  // Does block size seems reasonable?
+  if (_size >= max_reasonable_malloc_size) {
+    *p_corruption = (address)this;
+    jio_snprintf(msg, msglen, "header looks invalid (weirdly large block size)");
+    return false;
+  }
+
+  // Check footer canary
+  if (get_footer() != _footer_canary_life_mark) {
+    *p_corruption = footer_address();
+    jio_snprintf(msg, msglen, "footer canary broken at " PTR_FORMAT " (buffer overflow?)",
+                p2i(footer_address()));
+    return false;
+  }
+  return true;
+}
+
+#endif // SHARE_SERVICES_MALLOCHEADER_INLINE_HPP