dumpstate: save background traces when a BR is captured.
Adds a call to perfetto --save-for-bugreport to bugreport.
If a background trace labeled with bugreport_score > 0 is
being recorded when dumpstate is invoked, the tracing daemon
will stop the trace and serialize it into a fixed location
(/data/misc/perfetto-traces/bugreport/systrace.pftrace).
If no background tracing is happening, the command is a no-op.
The trace saving happens in two stages:
1. In the very early stage of dumpstate, the trace is
snapshoted (if in progress). This prevents that further
dumpstate activity pushes out interesting contents from
the trace buffer.
2. In the later stages of dumpstate, the trace is attached
to the bugreport.zip file and cleaned up.
Bug: 170334305
Change-Id: I4278459697a5ed20b20ee99032884874a82a66be
diff --git a/cmds/dumpstate/dumpstate.cpp b/cmds/dumpstate/dumpstate.cpp
index a374c86..fbb0a18 100644
--- a/cmds/dumpstate/dumpstate.cpp
+++ b/cmds/dumpstate/dumpstate.cpp
@@ -175,6 +175,7 @@
#define SNAPSHOTCTL_LOG_DIR "/data/misc/snapshotctl_log"
#define LINKERCONFIG_DIR "/linkerconfig"
#define PACKAGE_DEX_USE_LIST "/data/system/package-dex-usage.list"
+#define SYSTEM_TRACE_SNAPSHOT "/data/misc/perfetto-traces/bugreport/systrace.pftrace"
// TODO(narayan): Since this information has to be kept in sync
// with tombstoned, we should just put it in a common header.
@@ -1053,6 +1054,24 @@
}
}
+static void MaybeAddSystemTraceToZip() {
+ // This function copies into the .zip the system trace that was snapshotted
+ // by the early call to MaybeSnapshotSystemTrace(), if any background
+ // tracing was happening.
+ if (!ds.IsZipping()) {
+ MYLOGD("Not dumping system trace because it's not a zipped bugreport\n");
+ return;
+ }
+ if (!ds.has_system_trace_) {
+ // No background trace was happening at the time dumpstate was invoked.
+ return;
+ }
+ ds.AddZipEntry(
+ ZIP_ROOT_DIR + SYSTEM_TRACE_SNAPSHOT,
+ SYSTEM_TRACE_SNAPSHOT);
+ android::os::UnlinkAndLogOnError(SYSTEM_TRACE_SNAPSHOT);
+}
+
static void DumpVisibleWindowViews() {
if (!ds.IsZipping()) {
MYLOGD("Not dumping visible views because it's not a zipped bugreport\n");
@@ -1649,6 +1668,8 @@
AddAnrTraceFiles();
+ MaybeAddSystemTraceToZip();
+
// NOTE: tombstones are always added as separate entries in the zip archive
// and are not interspersed with the main report.
const bool tombstones_dumped = AddDumps(ds.tombstone_data_.begin(), ds.tombstone_data_.end(),
@@ -2886,6 +2907,13 @@
RunDumpsysCritical();
}
MaybeTakeEarlyScreenshot();
+
+ if (!is_dumpstate_restricted) {
+ // Snapshot the system trace now (if running) to avoid that dumpstate's
+ // own activity pushes out interesting data from the trace ring buffer.
+ // The trace file is added to the zip by MaybeAddSystemTraceToZip().
+ MaybeSnapshotSystemTrace();
+ }
onUiIntensiveBugreportDumpsFinished(calling_uid);
MaybeCheckUserConsent(calling_uid, calling_package);
if (options_->telephony_only) {
@@ -2976,6 +3004,26 @@
TakeScreenshot();
}
+void Dumpstate::MaybeSnapshotSystemTrace() {
+ // If a background system trace is happening and is marked as "suitable for
+ // bugreport" (i.e. bugreport_score > 0 in the trace config), this command
+ // will stop it and serialize into SYSTEM_TRACE_SNAPSHOT. In the (likely)
+ // case that no trace is ongoing, this command is a no-op.
+ // Note: this should not be enqueued as we need to freeze the trace before
+ // dumpstate starts. Otherwise the trace ring buffers will contain mostly
+ // the dumpstate's own activity which is irrelevant.
+ int res = RunCommand(
+ "SERIALIZE PERFETTO TRACE",
+ {"perfetto", "--save-for-bugreport"},
+ CommandOptions::WithTimeout(10)
+ .DropRoot()
+ .CloseAllFileDescriptorsOnExec()
+ .Build());
+ has_system_trace_ = res == 0;
+ // MaybeAddSystemTraceToZip() will take care of copying the trace in the zip
+ // file in the later stages.
+}
+
void Dumpstate::onUiIntensiveBugreportDumpsFinished(int32_t calling_uid) {
if (calling_uid == AID_SHELL || !CalledByApi()) {
return;