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Fix crash that occurs if GetStats is called from within OnStatsDelivered

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This was resulting in the currently executing stats callback to be
invoked *again*, possibly ad infinitum, resulting in stack overflow.

Bug: webrtc:8973
Change-Id: Ib3bcc8e6bdd991728214fa242dda2010efc919a7
Reviewed-on: https://webrtc-review.googlesource.com/59464
Commit-Queue: Taylor Brandstetter <deadbeef@webrtc.org>
Reviewed-by: Henrik Boström <hbos@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#22313}
This commit is contained in:
Taylor Brandstetter
2018-03-06 09:42:25 -08:00
committed by Commit Bot
parent 12eb85881c
commit 87d5a7494a
2 changed files with 38 additions and 2 deletions
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9
pc/rtcstatscollector.cc
View File

@ -780,11 +780,16 @@ void RTCStatsCollector::DeliverCachedReport() {
RTC_DCHECK(signaling_thread_->IsCurrent());
RTC_DCHECK(!callbacks_.empty());
RTC_DCHECK(cached_report_);
// Swap the list of callbacks, in case one of them recursively calls
// GetStatsReport again and modifies the callback list.
std::vector<rtc::scoped_refptr<RTCStatsCollectorCallback>> callbacks;
callbacks.swap(callbacks_);
for (const rtc::scoped_refptr<RTCStatsCollectorCallback>& callback :
callbacks_) {
callbacks) {
callback->OnStatsDelivered(cached_report_);
}
callbacks_.clear();
}
void RTCStatsCollector::ProduceCertificateStats_n(

31
pc/rtcstatscollector_unittest.cc
View File

@ -1910,6 +1910,37 @@ TEST_F(RTCStatsCollectorTest, DoNotCrashOnSsrcChange) {
EXPECT_EQ(1, track_stats.size());
}
// Used for test below, to test calling GetStatsReport during a callback.
class ReentrantCallback : public RTCStatsCollectorCallback {
public:
explicit ReentrantCallback(RTCStatsCollectorWrapper* stats) : stats_(stats) {}
void OnStatsDelivered(
const rtc::scoped_refptr<const RTCStatsReport>& report) override {
stats_->GetStatsReport();
called_ = true;
}
bool called() const { return called_; }
private:
RTCStatsCollectorWrapper* stats_;
bool called_ = false;
};
// Test that nothing bad happens if a callback causes GetStatsReport to be
// called again recursively. Regression test for crbug.com/webrtc/8973.
TEST_F(RTCStatsCollectorTest, DoNotCrashOnReentrantInvocation) {
rtc::scoped_refptr<ReentrantCallback> callback1(
new rtc::RefCountedObject<ReentrantCallback>(stats_.get()));
rtc::scoped_refptr<ReentrantCallback> callback2(
new rtc::RefCountedObject<ReentrantCallback>(stats_.get()));
stats_->stats_collector()->GetStatsReport(callback1);
stats_->stats_collector()->GetStatsReport(callback2);
EXPECT_TRUE_WAIT(callback1->called(), kGetStatsReportTimeoutMs);
EXPECT_TRUE_WAIT(callback2->called(), kGetStatsReportTimeoutMs);
}
class RTCTestStats : public RTCStats {
public:
WEBRTC_RTCSTATS_DECL();