Compare new unwinder to old unwinder in debuggerd.
In debuggerd, when dumping a tombstone, run the new unwinder and verify
the old and new unwinder are the same. If not, dump enough information
in the tombstones to figure out how to duplicate the failure.
Bug: 23762183
Test: Builds, ran and forced a mismatch and verified output.
Change-Id: Ia178bde64d67e623d4f35086ebda68aebbff0c3c
diff --git a/debuggerd/Android.bp b/debuggerd/Android.bp
index f86aaa0..7d17cd9 100644
--- a/debuggerd/Android.bp
+++ b/debuggerd/Android.bp
@@ -106,6 +106,7 @@
"libdebuggerd",
"libbacktrace",
"libunwind",
+ "libunwindstack",
"liblzma",
"libcutils",
],
@@ -171,6 +172,7 @@
static_libs: [
"libbacktrace",
"libunwind",
+ "libunwindstack",
"liblzma",
"libbase",
"libcutils",
diff --git a/debuggerd/crash_dump.cpp b/debuggerd/crash_dump.cpp
index 4b1e51d..34ad7de 100644
--- a/debuggerd/crash_dump.cpp
+++ b/debuggerd/crash_dump.cpp
@@ -329,6 +329,11 @@
LOG(FATAL) << "failed to create backtrace map";
}
}
+ std::unique_ptr<BacktraceMap> backtrace_map_new;
+ backtrace_map_new.reset(BacktraceMap::CreateNew(main_tid));
+ if (!backtrace_map_new) {
+ LOG(FATAL) << "failed to create backtrace map new";
+ }
// Collect the list of open files.
OpenFilesList open_files;
@@ -408,8 +413,9 @@
dump_backtrace(output_fd.get(), backtrace_map.get(), target, main_tid, process_name, threads, 0);
} else {
ATRACE_NAME("engrave_tombstone");
- engrave_tombstone(output_fd.get(), backtrace_map.get(), &open_files, target, main_tid,
- process_name, threads, abort_address, fatal_signal ? &amfd_data : nullptr);
+ engrave_tombstone(output_fd.get(), backtrace_map.get(), backtrace_map_new.get(), &open_files,
+ target, main_tid, process_name, threads, abort_address,
+ fatal_signal ? &amfd_data : nullptr);
}
// We don't actually need to PTRACE_DETACH, as long as our tracees aren't in
diff --git a/debuggerd/libdebuggerd/include/tombstone.h b/debuggerd/libdebuggerd/include/tombstone.h
index 79743b6..45740df 100644
--- a/debuggerd/libdebuggerd/include/tombstone.h
+++ b/debuggerd/libdebuggerd/include/tombstone.h
@@ -35,10 +35,10 @@
int open_tombstone(std::string* path);
/* Creates a tombstone file and writes the crash dump to it. */
-void engrave_tombstone(int tombstone_fd, BacktraceMap* map, const OpenFilesList* open_files,
- pid_t pid, pid_t tid, const std::string& process_name,
- const std::map<pid_t, std::string>& threads, uintptr_t abort_msg_address,
- std::string* amfd_data);
+void engrave_tombstone(int tombstone_fd, BacktraceMap* map, BacktraceMap* map_new,
+ const OpenFilesList* open_files, pid_t pid, pid_t tid,
+ const std::string& process_name, const std::map<pid_t, std::string>& threads,
+ uintptr_t abort_msg_address, std::string* amfd_data);
void engrave_tombstone_ucontext(int tombstone_fd, uintptr_t abort_msg_address, siginfo_t* siginfo,
ucontext_t* ucontext);
diff --git a/debuggerd/libdebuggerd/tombstone.cpp b/debuggerd/libdebuggerd/tombstone.cpp
index 0113131..b809ed4 100644
--- a/debuggerd/libdebuggerd/tombstone.cpp
+++ b/debuggerd/libdebuggerd/tombstone.cpp
@@ -495,8 +495,55 @@
_LOG(log, logtype::REGISTERS, " register dumping unimplemented on this architecture");
}
-static void dump_thread(log_t* log, pid_t pid, pid_t tid, const std::string& process_name,
- const std::string& thread_name, BacktraceMap* map,
+static bool verify_backtraces_equal(Backtrace* back1, Backtrace* back2) {
+ if (back1->NumFrames() != back2->NumFrames()) {
+ return false;
+ }
+ std::string back1_str;
+ std::string back2_str;
+ for (size_t i = 0; i < back1->NumFrames(); i++) {
+ back1_str += back1->FormatFrameData(i);
+ back2_str += back2->FormatFrameData(i);
+ }
+ return back1_str == back2_str;
+}
+
+static void log_mismatch_data(log_t* log, Backtrace* backtrace) {
+ _LOG(log, logtype::THREAD, "MISMATCH: This unwind is different.\n");
+ if (backtrace->NumFrames() == 0) {
+ _LOG(log, logtype::THREAD, "MISMATCH: No frames in new backtrace.\n");
+ return;
+ }
+ _LOG(log, logtype::THREAD, "MISMATCH: Backtrace from new unwinder.\n");
+ for (size_t i = 0; i < backtrace->NumFrames(); i++) {
+ _LOG(log, logtype::THREAD, "MISMATCH: %s\n", backtrace->FormatFrameData(i).c_str());
+ }
+
+ // Get the stack trace up to 8192 bytes.
+ std::vector<uint64_t> buffer(8192 / sizeof(uint64_t));
+ size_t bytes =
+ backtrace->Read(backtrace->GetFrame(0)->sp, reinterpret_cast<uint8_t*>(buffer.data()),
+ buffer.size() * sizeof(uint64_t));
+ std::string log_data;
+ for (size_t i = 0; i < bytes / sizeof(uint64_t); i++) {
+ if ((i % 4) == 0) {
+ if (!log_data.empty()) {
+ _LOG(log, logtype::THREAD, "MISMATCH: stack_data%s\n", log_data.c_str());
+ log_data = "";
+ }
+ }
+ log_data += android::base::StringPrintf(" 0x%016" PRIx64, buffer[i]);
+ }
+
+ if (!log_data.empty()) {
+ _LOG(log, logtype::THREAD, "MISMATCH: data%s\n", log_data.c_str());
+ }
+
+ // If there is any leftover (bytes % sizeof(uint64_t) != 0, ignore it for now.
+}
+
+static bool dump_thread(log_t* log, pid_t pid, pid_t tid, const std::string& process_name,
+ const std::string& thread_name, BacktraceMap* map, BacktraceMap* map_new,
uintptr_t abort_msg_address, bool primary_thread) {
log->current_tid = tid;
if (!primary_thread) {
@@ -510,7 +557,18 @@
dump_abort_message(backtrace.get(), log, abort_msg_address);
}
dump_registers(log, tid);
+ bool matches = true;
if (backtrace->Unwind(0)) {
+ // Use the new method and verify it is the same as old.
+ std::unique_ptr<Backtrace> backtrace_new(Backtrace::CreateNew(pid, tid, map_new));
+ if (!backtrace_new->Unwind(0)) {
+ _LOG(log, logtype::THREAD, "Failed to unwind with new unwinder: %s\n",
+ backtrace_new->GetErrorString(backtrace_new->GetError()).c_str());
+ matches = false;
+ } else if (!verify_backtraces_equal(backtrace.get(), backtrace_new.get())) {
+ log_mismatch_data(log, backtrace_new.get());
+ matches = false;
+ }
dump_backtrace_and_stack(backtrace.get(), log);
} else {
ALOGE("Unwind failed: pid = %d, tid = %d", pid, tid);
@@ -524,6 +582,8 @@
}
log->current_tid = log->crashed_tid;
+
+ return matches;
}
// Reads the contents of the specified log device, filters out the entries
@@ -657,9 +717,10 @@
}
// Dumps all information about the specified pid to the tombstone.
-static void dump_crash(log_t* log, BacktraceMap* map, const OpenFilesList* open_files, pid_t pid,
- pid_t tid, const std::string& process_name,
- const std::map<pid_t, std::string>& threads, uintptr_t abort_msg_address) {
+static void dump_crash(log_t* log, BacktraceMap* map, BacktraceMap* map_new,
+ const OpenFilesList* open_files, pid_t pid, pid_t tid,
+ const std::string& process_name, const std::map<pid_t, std::string>& threads,
+ uintptr_t abort_msg_address) {
// don't copy log messages to tombstone unless this is a dev device
char value[PROPERTY_VALUE_MAX];
property_get("ro.debuggable", value, "0");
@@ -668,7 +729,8 @@
_LOG(log, logtype::HEADER,
"*** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***\n");
dump_header_info(log);
- dump_thread(log, pid, tid, process_name, threads.find(tid)->second, map, abort_msg_address, true);
+ bool new_unwind_matches = dump_thread(log, pid, tid, process_name, threads.find(tid)->second, map,
+ map_new, abort_msg_address, true);
if (want_logs) {
dump_logs(log, pid, 5);
}
@@ -678,7 +740,9 @@
const std::string& thread_name = it.second;
if (thread_tid != tid) {
- dump_thread(log, pid, thread_tid, process_name, thread_name, map, 0, false);
+ bool match =
+ dump_thread(log, pid, thread_tid, process_name, thread_name, map, map_new, 0, false);
+ new_unwind_matches = new_unwind_matches && match;
}
}
@@ -690,6 +754,14 @@
if (want_logs) {
dump_logs(log, pid, 0);
}
+ if (!new_unwind_matches) {
+ _LOG(log, logtype::THREAD, "MISMATCH: New and old unwinder do not agree.\n");
+ _LOG(log, logtype::THREAD, "MISMATCH: If you see this please file a bug in:\n");
+ _LOG(log, logtype::THREAD,
+ "MISMATCH: Android > Android OS & Apps > Runtime > native > tools "
+ "(debuggerd/gdb/init/simpleperf/strace/valgrind)\n");
+ _LOG(log, logtype::THREAD, "MISMATCH: and attach this tombstone.\n");
+ }
}
// open_tombstone - find an available tombstone slot, if any, of the
@@ -745,16 +817,16 @@
return fd;
}
-void engrave_tombstone(int tombstone_fd, BacktraceMap* map, const OpenFilesList* open_files,
- pid_t pid, pid_t tid, const std::string& process_name,
- const std::map<pid_t, std::string>& threads, uintptr_t abort_msg_address,
- std::string* amfd_data) {
+void engrave_tombstone(int tombstone_fd, BacktraceMap* map, BacktraceMap* map_new,
+ const OpenFilesList* open_files, pid_t pid, pid_t tid,
+ const std::string& process_name, const std::map<pid_t, std::string>& threads,
+ uintptr_t abort_msg_address, std::string* amfd_data) {
log_t log;
log.current_tid = tid;
log.crashed_tid = tid;
log.tfd = tombstone_fd;
log.amfd_data = amfd_data;
- dump_crash(&log, map, open_files, pid, tid, process_name, threads, abort_msg_address);
+ dump_crash(&log, map, map_new, open_files, pid, tid, process_name, threads, abort_msg_address);
}
void engrave_tombstone_ucontext(int tombstone_fd, uintptr_t abort_msg_address, siginfo_t* siginfo,