Merge "Update comments now that mPackages is no longer a lock" (485167c5) · Commits · e / os / android_frameworks_base

services/core/java/com/android/server/pm/PackageManagerService.java

+14 −14

Original line number	Diff line number	Diff line
		@@ -378,14 +378,14 @@ import java.util.function.Predicate;
		* <p>
		* Internally there are two important locks:
		* <ul>
		* <li>{@link #mPackages} is used to guard all in-memory parsed package details
		* <li>{@link #mLock} is used to guard all in-memory parsed package details
		* and other related state. It is a fine-grained lock that should only be held
		* momentarily, as it's one of the most contended locks in the system.
		* <li>{@link #mInstallLock} is used to guard all {@code installd} access, whose
		* operations typically involve heavy lifting of application data on disk. Since
		* {@code installd} is single-threaded, and it's operations can often be slow,
		* this lock should never be acquired while already holding {@link #mPackages}.
		* Conversely, it's safe to acquire {@link #mPackages} momentarily while already
		* this lock should never be acquired while already holding {@link #mLock}.
		* Conversely, it's safe to acquire {@link #mLock} momentarily while already
		* holding {@link #mInstallLock}.
		* </ul>
		* Many internal methods rely on the caller to hold the appropriate locks, and
		@@ -394,8 +394,8 @@ import java.util.function.Predicate;
		* <li>fooLI(): the caller must hold {@link #mInstallLock}
		* <li>fooLIF(): the caller must hold {@link #mInstallLock} and the package
		* being modified must be frozen
		* <li>fooLPr(): the caller must hold {@link #mPackages} for reading
		* <li>fooLPw(): the caller must hold {@link #mPackages} for writing
		* <li>fooLPr(): the caller must hold {@link #mLock} for reading
		* <li>fooLPw(): the caller must hold {@link #mLock} for writing
		* </ul>
		* <p>
		* Because this class is very central to the platform's security; please run all
		@@ -669,7 +669,7 @@ public class PackageManagerService extends IPackageManager.Stub

		// Lock for global state used when modifying package state or settings.
		// Methods that must be called with this lock held have
		// the suffix "Locked". Some methods may use the legacy the suffix "LP"
		// the suffix "Locked". Some methods may use the legacy suffix "LP"
		final Object mLock;

		// Keys are String (package name), values are Package.
		@@ -6531,13 +6531,13 @@ public class PackageManagerService extends IPackageManager.Stub
		}

		// TODO: handle preferred activities missing while user has amnesia
		/** <b>must not hold {@link #mPackages}</b> */
		/** <b>must not hold {@link #mLock}</b> */
		ResolveInfo findPreferredActivityNotLocked(Intent intent, String resolvedType, int flags,
		List<ResolveInfo> query, int priority, boolean always,
		boolean removeMatches, boolean debug, int userId) {
		if (Thread.holdsLock(mLock)) {
		Slog.wtf(TAG, "Calling thread " + Thread.currentThread().getName()
		+ " is holding mPackages", new Throwable());
		+ " is holding mLock", new Throwable());
		}
		if (!mUserManager.exists(userId)) return null;
		final int callingUid = Binder.getCallingUid();
		@@ -16195,7 +16195,7 @@ public class PackageManagerService extends IPackageManager.Stub
		/**
		* On successful install, executes remaining steps after commit completes and the package lock
		* is released. These are typically more expensive or require calls to installd, which often
		* locks on {@link #mPackages}.
		* locks on {@link #mLock}.
		*/
		private void executePostCommitSteps(CommitRequest commitRequest) {
		for (ReconciledPackage reconciledPkg : commitRequest.reconciledPackages.values()) {
		@@ -19872,11 +19872,11 @@ public class PackageManagerService extends IPackageManager.Stub
		return null;
		}

		/** <b>must not hold {@link #mPackages}</b> */
		/** <b>must not hold {@link #mLock}</b> */
		private void updateDefaultHomeNotLocked(SparseBooleanArray userIds) {
		if (Thread.holdsLock(mLock)) {
		Slog.wtf(TAG, "Calling thread " + Thread.currentThread().getName()
		+ " is holding mPackages", new Throwable());
		+ " is holding mLock", new Throwable());
		}
		for (int i = userIds.size() - 1; i >= 0; --i) {
		final int userId = userIds.keyAt(i);
		@@ -19885,14 +19885,14 @@ public class PackageManagerService extends IPackageManager.Stub
		}

		/**
		* <b>must not hold {@link #mPackages}</b>
		* <b>must not hold {@link #mLock}</b>
		*
		* @return Whether the ACTION_PREFERRED_ACTIVITY_CHANGED broadcast has been scheduled.
		*/
		private boolean updateDefaultHomeNotLocked(int userId) {
		if (Thread.holdsLock(mLock)) {
		Slog.wtf(TAG, "Calling thread " + Thread.currentThread().getName()
		+ " is holding mPackages", new Throwable());
		+ " is holding mLock", new Throwable());
		}
		if (!mSystemReady) {
		// We might get called before system is ready because of package changes etc, but
		@@ -21823,7 +21823,7 @@ public class PackageManagerService extends IPackageManager.Stub
		* will try recovering system apps by wiping data; third-party app data is
		* left intact.
		* <p>
		* <em>Note: To avoid a deadlock, do not call this method with {@code mPackages} lock held</em>
		* <em>Note: To avoid a deadlock, do not call this method with {@code mLock} lock held</em>
		*/
		private void prepareAppDataAfterInstallLIF(PackageParser.Package pkg) {
		final PackageSetting ps;