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Fixing multithreading issues in Ethernet Factory

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IP client callbacks could be executed updating the state of an
ethernet interface even if they were no longer the callbacks for the
currently active interface. This can happen as IP client callbacks
were being called from a thread separate from ethernet.

Bug: 224890356
Test: atest EthernetServiceTests
atest CtsNetTestCasesLatestSdk
:android.net.cts.EthernetManagerTest --iterations 30

Change-Id: I238cb75caa01472bccc79db5bafa82bccdaeba52
This commit is contained in:
James Mattis
2022-03-15 21:42:10 -07:00
parent 641bc0c4dc
commit de503c5a44
2 changed files with 53 additions and 63 deletions
Download Patch File Download Diff File Expand all files Collapse all files

50
service-t/src/com/android/server/ethernet/EthernetNetworkFactory.java
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@@ -439,24 +439,44 @@ public class EthernetNetworkFactory extends NetworkFactory {
mIpClientShutdownCv.block();
}
// At the time IpClient is stopped, an IpClient event may have already been posted on
// the back of the handler and is awaiting execution. Once that event is executed, the
// associated callback object may not be valid anymore
// (NetworkInterfaceState#mIpClientCallback points to a different object / null).
private boolean isCurrentCallback() {
return this == mIpClientCallback;
}
private void handleIpEvent(final @NonNull Runnable r) {
mHandler.post(() -> {
if (!isCurrentCallback()) {
Log.i(TAG, "Ignoring stale IpClientCallbacks " + this);
return;
}
r.run();
});
}
@Override
public void onProvisioningSuccess(LinkProperties newLp) {
mHandler.post(() -> onIpLayerStarted(newLp, mNetworkManagementListener));
handleIpEvent(() -> onIpLayerStarted(newLp, mNetworkManagementListener));
}
@Override
public void onProvisioningFailure(LinkProperties newLp) {
mHandler.post(() -> onIpLayerStopped(mNetworkManagementListener));
// This cannot happen due to provisioning timeout, because our timeout is 0. It can
// happen due to errors while provisioning or on provisioning loss.
handleIpEvent(() -> onIpLayerStopped(mNetworkManagementListener));
}
@Override
public void onLinkPropertiesChange(LinkProperties newLp) {
mHandler.post(() -> updateLinkProperties(newLp));
handleIpEvent(() -> updateLinkProperties(newLp));
}
@Override
public void onReachabilityLost(String logMsg) {
mHandler.post(() -> updateNeighborLostEvent(logMsg));
handleIpEvent(() -> updateNeighborLostEvent(logMsg));
}
@Override
@@ -558,14 +578,6 @@ public class EthernetNetworkFactory extends NetworkFactory {
void onIpLayerStarted(@NonNull final LinkProperties linkProperties,
@Nullable final INetworkInterfaceOutcomeReceiver listener) {
if(mIpClient == null) {
// This call comes from a message posted on the handler thread, but the IpClient has
// since been stopped such as may be the case if updateInterfaceLinkState() is
// queued on the handler thread prior. As network management callbacks are sent in
// stop(), there is no need to send them again here.
if (DBG) Log.d(TAG, "IpClient is not initialized.");
return;
}
if (mNetworkAgent != null) {
Log.e(TAG, "Already have a NetworkAgent - aborting new request");
stop();
@@ -601,12 +613,6 @@ public class EthernetNetworkFactory extends NetworkFactory {
}
void onIpLayerStopped(@Nullable final INetworkInterfaceOutcomeReceiver listener) {
// This cannot happen due to provisioning timeout, because our timeout is 0. It can
// happen due to errors while provisioning or on provisioning loss.
if(mIpClient == null) {
if (DBG) Log.d(TAG, "IpClient is not initialized.");
return;
}
// There is no point in continuing if the interface is gone as stop() will be triggered
// by removeInterface() when processed on the handler thread and start() won't
// work for a non-existent interface.
@@ -648,10 +654,6 @@ public class EthernetNetworkFactory extends NetworkFactory {
}
void updateLinkProperties(LinkProperties linkProperties) {
if(mIpClient == null) {
if (DBG) Log.d(TAG, "IpClient is not initialized.");
return;
}
mLinkProperties = linkProperties;
if (mNetworkAgent != null) {
mNetworkAgent.sendLinkPropertiesImpl(linkProperties);
@@ -659,10 +661,6 @@ public class EthernetNetworkFactory extends NetworkFactory {
}
void updateNeighborLostEvent(String logMsg) {
if(mIpClient == null) {
if (DBG) Log.d(TAG, "IpClient is not initialized.");
return;
}
Log.i(TAG, "updateNeighborLostEvent " + logMsg);
// Reachability lost will be seen only if the gateway is not reachable.
// Since ethernet FW doesn't have the mechanism to scan for new networks