Add support for MTE error reports in tombstones.
Teach debuggerd to use the new scudo APIs proposed in
https://reviews.llvm.org/D77283 for extracing MTE error reports from crashed
processes, and include those reports in tombstones if possible.
Bug: 135772972
Change-Id: I082dfd0ac9d781cfed2b8c34cc73562614bb0dbb
diff --git a/debuggerd/libdebuggerd/scudo.cpp b/debuggerd/libdebuggerd/scudo.cpp
new file mode 100644
index 0000000..f8bfe07
--- /dev/null
+++ b/debuggerd/libdebuggerd/scudo.cpp
@@ -0,0 +1,159 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "libdebuggerd/scudo.h"
+#include "libdebuggerd/gwp_asan.h"
+
+#include "unwindstack/Memory.h"
+#include "unwindstack/Unwinder.h"
+
+#include <bionic/macros.h>
+
+std::unique_ptr<char[]> AllocAndReadFully(unwindstack::Memory* process_memory, uint64_t addr,
+ size_t size) {
+ auto buf = std::make_unique<char[]>(size);
+ if (!process_memory->ReadFully(addr, buf.get(), size)) {
+ return std::unique_ptr<char[]>();
+ }
+ return buf;
+}
+
+static const uintptr_t kTagGranuleSize = 16;
+
+ScudoCrashData::ScudoCrashData(unwindstack::Memory* process_memory,
+ const ProcessInfo& process_info) {
+ if (!process_info.has_fault_address) {
+ return;
+ }
+
+ auto stack_depot = AllocAndReadFully(process_memory, process_info.scudo_stack_depot,
+ __scudo_get_stack_depot_size());
+ auto region_info = AllocAndReadFully(process_memory, process_info.scudo_region_info,
+ __scudo_get_region_info_size());
+
+ untagged_fault_addr_ = untag_address(process_info.fault_address);
+ uintptr_t fault_page = untagged_fault_addr_ & ~(PAGE_SIZE - 1);
+
+ uintptr_t memory_begin = fault_page - PAGE_SIZE * 16;
+ if (memory_begin > fault_page) {
+ return;
+ }
+
+ uintptr_t memory_end = fault_page + PAGE_SIZE * 16;
+ if (memory_end < fault_page) {
+ return;
+ }
+
+ auto memory = std::make_unique<char[]>(memory_end - memory_begin);
+ for (auto i = memory_begin; i != memory_end; i += PAGE_SIZE) {
+ process_memory->ReadFully(i, memory.get() + i - memory_begin, PAGE_SIZE);
+ }
+
+ auto memory_tags = std::make_unique<char[]>((memory_end - memory_begin) / kTagGranuleSize);
+ for (auto i = memory_begin; i != memory_end; i += kTagGranuleSize) {
+ memory_tags[(i - memory_begin) / kTagGranuleSize] = process_memory->ReadTag(i);
+ }
+
+ __scudo_get_error_info(&error_info_, process_info.fault_address, stack_depot.get(),
+ region_info.get(), memory.get(), memory_tags.get(), memory_begin,
+ memory_end - memory_begin);
+}
+
+bool ScudoCrashData::CrashIsMine() const {
+ return error_info_.reports[0].error_type != UNKNOWN;
+}
+
+void ScudoCrashData::DumpCause(log_t* log, unwindstack::Unwinder* unwinder) const {
+ if (error_info_.reports[1].error_type != UNKNOWN) {
+ _LOG(log, logtype::HEADER,
+ "\nNote: multiple potential causes for this crash were detected, listing them in "
+ "decreasing order of probability.\n");
+ }
+
+ size_t report_num = 0;
+ while (report_num < sizeof(error_info_.reports) / sizeof(error_info_.reports[0]) &&
+ error_info_.reports[report_num].error_type != UNKNOWN) {
+ DumpReport(&error_info_.reports[report_num++], log, unwinder);
+ }
+}
+
+void ScudoCrashData::DumpReport(const scudo_error_report* report, log_t* log,
+ unwindstack::Unwinder* unwinder) const {
+ const char *error_type_str;
+ switch (report->error_type) {
+ case USE_AFTER_FREE:
+ error_type_str = "Use After Free";
+ break;
+ case BUFFER_OVERFLOW:
+ error_type_str = "Buffer Overflow";
+ break;
+ case BUFFER_UNDERFLOW:
+ error_type_str = "Buffer Underflow";
+ break;
+ default:
+ error_type_str = "Unknown";
+ break;
+ }
+
+ uintptr_t diff;
+ const char* location_str;
+
+ if (untagged_fault_addr_ < report->allocation_address) {
+ // Buffer Underflow, 6 bytes left of a 41-byte allocation at 0xdeadbeef.
+ location_str = "left of";
+ diff = report->allocation_address - untagged_fault_addr_;
+ } else if (untagged_fault_addr_ - report->allocation_address < report->allocation_size) {
+ // Use After Free, 40 bytes into a 41-byte allocation at 0xdeadbeef.
+ location_str = "into";
+ diff = untagged_fault_addr_ - report->allocation_address;
+ } else {
+ // Buffer Overflow, 6 bytes right of a 41-byte allocation at 0xdeadbeef.
+ location_str = "right of";
+ diff = untagged_fault_addr_ - report->allocation_address - report->allocation_size;
+ }
+
+ // Suffix of 'bytes', i.e. 4 bytes' vs. '1 byte'.
+ const char* byte_suffix = "s";
+ if (diff == 1) {
+ byte_suffix = "";
+ }
+ _LOG(log, logtype::HEADER,
+ "\nCause: [MTE]: %s, %" PRIuPTR " byte%s %s a %zu-byte allocation at 0x%" PRIxPTR "\n",
+ error_type_str, diff, byte_suffix, location_str, report->allocation_size,
+ report->allocation_address);
+
+ if (report->allocation_trace[0]) {
+ _LOG(log, logtype::BACKTRACE, "\nallocated by thread %u:\n", report->allocation_tid);
+ unwinder->SetDisplayBuildID(true);
+ for (size_t i = 0; i < 64 && report->allocation_trace[i]; ++i) {
+ unwindstack::FrameData frame_data =
+ unwinder->BuildFrameFromPcOnly(report->allocation_trace[i]);
+ frame_data.num = i;
+ _LOG(log, logtype::BACKTRACE, " %s\n", unwinder->FormatFrame(frame_data).c_str());
+ }
+ }
+
+ if (report->deallocation_trace[0]) {
+ _LOG(log, logtype::BACKTRACE, "\ndeallocated by thread %u:\n", report->deallocation_tid);
+ unwinder->SetDisplayBuildID(true);
+ for (size_t i = 0; i < 64 && report->deallocation_trace[i]; ++i) {
+ unwindstack::FrameData frame_data =
+ unwinder->BuildFrameFromPcOnly(report->deallocation_trace[i]);
+ frame_data.num = i;
+ _LOG(log, logtype::BACKTRACE, " %s\n", unwinder->FormatFrame(frame_data).c_str());
+ }
+ }
+}