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Commit 703cf10c authored by Hui Yu's avatar Hui Yu
Browse files

Synchronize on the SparseArray object in PendingTempAllowlists. 

The field mPendingTempAllowlist in PendingTempAllowlists is a
SparseArray.

In ActivityManagerService, the lock protection for PendingTempAllowlists
object is:
 @CompositeRWLock({"this", "mProcLock"})
    final PendingTempAllowlists mPendingTempAllowlist

Which means the mPendingTempAllowlist object can be read when either
"this" lock or "mProcLock" lock is held. But the read-operation of
SparseArray such as indexOfKey() and size() etc, actually mutate the
SparseArray by calling SparseArray.gc(). This makes @CompositeRWLock not
to be compatible with SparseArray.

Since we can not make SparseArray thread-safe, also we want to maintain
the semantic of @CompositeRWLock, we can make
PendingTempAllowlists thread-safe at least.

Bug: 193788840
Test: Regression test.
Change-Id: Ie1c239ad27d1fd6b76676951b470605513848b20
parent da94cf36

services/core/java/com/android/server/am/ActivityManagerService.java

+8 −6
Original line number Diff line number Diff line
@@ -5823,7 +5823,7 @@ public class ActivityManagerService extends IActivityManager.Stub 














        return Arrays.binarySearch(allowlist, appId) >= 0















                || Arrays.binarySearch(mDeviceIdleTempAllowlist, appId) >= 0













                || mPendingTempAllowlist.indexOfKey(uid) >= 0;













                || mPendingTempAllowlist.get(uid) != null;















    }





























    /**










@@ -15122,6 +15122,7 @@ public class ActivityManagerService extends IActivityManager.Stub



























        // First copy out the pending changes...  we need to leave them in the map for now,















        // in case someone needs to check what is coming up while we don't have the lock held.













        synchronized (this) {















            synchronized (mProcLock) {















                N = mPendingTempAllowlist.size();















                list = new PendingTempAllowlist[N];









@@ -15129,6 +15130,7 @@ public class ActivityManagerService extends IActivityManager.Stub













                    list[i] = mPendingTempAllowlist.valueAt(i);















                }















            }













        }





























        // Now safely dispatch changes to device idle controller.  Skip this if we're early















        // in boot and the controller hasn't yet been brought online:  we do not apply

























services/core/java/com/android/server/am/PendingTempAllowlists.java



+22
−7




























Original line number
Diff line number
Diff line








@@ -16,6 +16,8 @@





























package com.android.server.am;





























import static android.os.Process.INVALID_UID;





























import android.util.SparseArray;































/** Allowlists of uids to temporarily bypass Power Save mode. */









@@ -31,29 +33,42 @@ final class PendingTempAllowlists {













    }































    void put(int uid, ActivityManagerService.PendingTempAllowlist value) {













        synchronized (mPendingTempAllowlist) {















            mPendingTempAllowlist.put(uid, value);













        }















        mService.mAtmInternal.onUidAddedToPendingTempAllowlist(uid, value.tag);















    }































    void removeAt(int index) {













        final int uid = mPendingTempAllowlist.keyAt(index);













        int uid = INVALID_UID;













        synchronized (mPendingTempAllowlist) {













            uid = mPendingTempAllowlist.keyAt(index);















            mPendingTempAllowlist.removeAt(index);













        }















        mService.mAtmInternal.onUidRemovedFromPendingTempAllowlist(uid);















    }































    ActivityManagerService.PendingTempAllowlist get(int uid) {













        synchronized (mPendingTempAllowlist) {















            return mPendingTempAllowlist.get(uid);















        }













    }































    int size() {













        synchronized (mPendingTempAllowlist) {















            return mPendingTempAllowlist.size();















        }













    }































    ActivityManagerService.PendingTempAllowlist valueAt(int index) {













        synchronized (mPendingTempAllowlist) {















            return mPendingTempAllowlist.valueAt(index);















        }













    }































    int indexOfKey(int key) {













        synchronized (mPendingTempAllowlist) {















            return mPendingTempAllowlist.indexOfKey(key);















        }















    }













}