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Run addUidToObserver and removeUidFromObserver on the handler thread.

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If we're in dispatchUidsChanged while another thread is calling
addUidToObserver or removeUidFromObserver, there will be two active
broadcasts for mUidObservers. Move this processing to the handler thread
to eliminate the possibility of this race condition.

Change-Id: I9d64978415ebb42f194936ec56ba9933ed1533e7
Bug: 285982408
Test: Ran testCamera2AccessCallbackInSplitMode
This commit is contained in:
Austin Borger
2023-06-06 12:46:07 -07:00
parent 9a5bc75e81
commit 345a42452b
2 changed files with 61 additions and 30 deletions
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8
services/core/java/com/android/server/am/ActivityManagerService.java
View File

@@ -1616,6 +1616,8 @@ public class ActivityManagerService extends IActivityManager.Stub
static final int SERVICE_SHORT_FGS_PROCSTATE_TIMEOUT_MSG = 77;
static final int SERVICE_SHORT_FGS_ANR_TIMEOUT_MSG = 78;
static final int UPDATE_CACHED_APP_HIGH_WATERMARK = 79;
static final int ADD_UID_TO_OBSERVER_MSG = 80;
static final int REMOVE_UID_FROM_OBSERVER_MSG = 81;
static final int FIRST_BROADCAST_QUEUE_MSG = 200;
@@ -1774,6 +1776,12 @@ public class ActivityManagerService extends IActivityManager.Stub
case PUSH_TEMP_ALLOWLIST_UI_MSG: {
pushTempAllowlist();
} break;
case ADD_UID_TO_OBSERVER_MSG: {
mUidObserverController.addUidToObserverImpl((IBinder) msg.obj, msg.arg1);
} break;
case REMOVE_UID_FROM_OBSERVER_MSG: {
mUidObserverController.removeUidFromObserverImpl((IBinder) msg.obj, msg.arg1);
} break;
}
}
}

83
services/core/java/com/android/server/am/UidObserverController.java
View File

@@ -30,6 +30,7 @@ import android.content.pm.PackageManager;
import android.os.Binder;
import android.os.Handler;
import android.os.IBinder;
import android.os.Message;
import android.os.RemoteCallbackList;
import android.os.RemoteException;
import android.os.SystemClock;
@@ -104,40 +105,62 @@ public class UidObserverController {
}
}
void addUidToObserver(@NonNull IBinder observerToken, int uid) {
synchronized (mLock) {
int i = mUidObservers.beginBroadcast();
while (i-- > 0) {
var reg = (UidObserverRegistration) mUidObservers.getBroadcastCookie(i);
if (reg.getToken().equals(observerToken)) {
reg.addUid(uid);
break;
}
if (i == 0) {
Slog.e(TAG_UID_OBSERVERS, "Unable to find UidObserver by token");
}
}
mUidObservers.finishBroadcast();
}
final void addUidToObserver(@NonNull IBinder observerToken, int uid) {
Message msg = Message.obtain(mHandler, ActivityManagerService.ADD_UID_TO_OBSERVER_MSG,
uid, /*arg2*/ 0, observerToken);
mHandler.sendMessage(msg);
}
void removeUidFromObserver(@NonNull IBinder observerToken, int uid) {
synchronized (mLock) {
int i = mUidObservers.beginBroadcast();
while (i-- > 0) {
var reg = (UidObserverRegistration) mUidObservers.getBroadcastCookie(i);
if (reg.getToken().equals(observerToken)) {
reg.removeUid(uid);
break;
}
if (i == 0) {
Slog.e(TAG_UID_OBSERVERS, "Unable to find UidObserver by token");
}
/**
* Add a uid to the list of uids an observer is interested in. Must be run on the same thread
* as mDispatchRunnable.
*
* @param observerToken The token identifier for a UidObserver
* @param uid The uid to add to the list of watched uids
*/
public final void addUidToObserverImpl(@NonNull IBinder observerToken, int uid) {
int i = mUidObservers.beginBroadcast();
while (i-- > 0) {
var reg = (UidObserverRegistration) mUidObservers.getBroadcastCookie(i);
if (reg.getToken().equals(observerToken)) {
reg.addUid(uid);
break;
}
if (i == 0) {
Slog.e(TAG_UID_OBSERVERS, "Unable to find UidObserver by token");
}
mUidObservers.finishBroadcast();
}
mUidObservers.finishBroadcast();
}
final void removeUidFromObserver(@NonNull IBinder observerToken, int uid) {
Message msg = Message.obtain(mHandler, ActivityManagerService.REMOVE_UID_FROM_OBSERVER_MSG,
uid, /*arg2*/ 0, observerToken);
mHandler.sendMessage(msg);
}
/**
* Remove a uid from the list of uids an observer is interested in. Must be run on the same
* thread as mDispatchRunnable.
*
* @param observerToken The token identifier for a UidObserver
* @param uid The uid to remove from the list of watched uids
*/
public final void removeUidFromObserverImpl(@NonNull IBinder observerToken, int uid) {
int i = mUidObservers.beginBroadcast();
while (i-- > 0) {
var reg = (UidObserverRegistration) mUidObservers.getBroadcastCookie(i);
if (reg.getToken().equals(observerToken)) {
reg.removeUid(uid);
break;
}
if (i == 0) {
Slog.e(TAG_UID_OBSERVERS, "Unable to find UidObserver by token");
}
}
mUidObservers.finishBroadcast();
}
int enqueueUidChange(@Nullable ChangeRecord currentRecord, int uid, int change, int procState,