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Commit 55af6c5f authored by Shunta Sato's avatar Shunta Sato Committed by Wale Ogunwale
Browse files

Avoid deadlock when installing app 

Symptom:
System crash is occurred by deadlock

Root cause:
ActivityManagerService's APIs usually hold a lock of itself instance.

In this case, four threads tried to take the same lock and it caused
deadlock.
Following three objects are in a three-cornered deadlocked.
- ActivityManagerService's instance
- PackageInstallerSession.mLock
- PackageManagerService.mPackages

Solution:
Call checkUidPermission before taking a lock of ActivityManagerService's
instance.

Fixes: 32425801
Test: manual
Author: Kazuki Nakayama <kazuki.x.nakayama@sonymobile.com>
Change-Id: I71ce57b1b8f3e0e9ba64b94a7b1f210b702efb6a
parent 9ac082f8

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

+2 −3
Original line number Diff line number Diff line
@@ -2810,14 +2810,13 @@ public final class ActiveServices { 
    }



    List<ActivityManager.RunningServiceInfo> getRunningServiceInfoLocked(int maxNum, int flags,

        int callingUid, boolean allowed) {

        int callingUid, boolean allowed, boolean canInteractAcrossUsers) {

        ArrayList<ActivityManager.RunningServiceInfo> res

                = new ArrayList<ActivityManager.RunningServiceInfo>();



        final long ident = Binder.clearCallingIdentity();

        try {

            if (ActivityManager.checkUidPermission(INTERACT_ACROSS_USERS_FULL, callingUid)

                == PERMISSION_GRANTED) {

            if (canInteractAcrossUsers) {

                int[] users = mAm.mUserController.getUsers();

                for (int ui=0; ui<users.length && res.size() < maxNum; ui++) {

                    ArrayMap<ComponentName, ServiceRecord> alls = getServicesLocked(users[ui]);

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

+8 −5
Original line number Diff line number Diff line
@@ -17506,12 +17506,15 @@ public class ActivityManagerService extends IActivityManager.Stub 
    public List<ActivityManager.RunningServiceInfo> getServices(int maxNum,

            int flags) {

        enforceNotIsolatedCaller("getServices");

        synchronized (this) {















        final int callingUid = Binder.getCallingUid();













        final boolean canInteractAcrossUsers = (ActivityManager.checkUidPermission(













            INTERACT_ACROSS_USERS_FULL, callingUid) == PERMISSION_GRANTED);















        final boolean allowed = isGetTasksAllowed("getServices", Binder.getCallingPid(),















            callingUid);

























            return mServices.getRunningServiceInfoLocked(maxNum, flags, callingUid, allowed);













        synchronized (this) {













            return mServices.getRunningServiceInfoLocked(maxNum, flags, callingUid,













                allowed, canInteractAcrossUsers);















        }















    }