Merge "Nuanced Uri handling related to WM/AM locking." into rvc-dev am: de5b073b05

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/12010084

Change-Id: I16d237eb3f1d4c458e2de915da1e3c9eda841515

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

@@ -8086,6 +8086,12 @@ public class ActivityManagerService extends IActivityManager.Stub
     }
 
     int checkContentProviderUriPermission(Uri uri, int userId, int callingUid, int modeFlags) {
+        if (Thread.holdsLock(mActivityTaskManager.getGlobalLock())) {
+            Slog.wtf(TAG, new IllegalStateException("Unable to check Uri permission"
+                    + " because caller is holding WM lock; assuming permission denied"));
+            return PackageManager.PERMISSION_DENIED;
+        }
+
         final String name = uri.getAuthority();
         final long ident = Binder.clearCallingIdentity();
         ContentProviderHolder holder = null;

services/core/java/com/android/server/wm/ActivityStarter.java

@@ -640,13 +640,10 @@ class ActivityStarter {
             }
 
             // If the caller hasn't already resolved the activity, we're willing
-            // to do so here, but because that may require acquiring the AM lock
-            // as part of calculating the NeededUriGrants, we must never hold
-            // the WM lock here to avoid deadlocking.
+            // to do so here. If the caller is already holding the WM lock here,
+            // and we need to check dynamic Uri permissions, then we're forced
+            // to assume those permissions are denied to avoid deadlocking.
             if (mRequest.activityInfo == null) {
-                if (Thread.holdsLock(mService.mGlobalLock)) {
-                    Slog.wtf(TAG, new IllegalStateException("Caller must not hold WM lock"));
-                }
                 mRequest.resolveActivity(mSupervisor);
             }