Merge "Fix the race condition between creating and killing process group" into udc-dev

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

@@ -2300,6 +2300,8 @@ public final class ProcessList {
 
             final Process.ProcessStartResult startResult;
             boolean regularZygote = false;
+            app.mProcessGroupCreated = false;
+            app.mSkipProcessGroupCreation = false;
             if (hostingRecord.usesWebviewZygote()) {
                 startResult = startWebView(entryPoint,
                         app.processName, uid, uid, gids, runtimeFlags, mountExternal,
@@ -2328,18 +2330,28 @@ public final class ProcessList {
                         isTopApp, app.getDisabledCompatChanges(), pkgDataInfoMap,
                         allowlistedAppDataInfoMap, bindMountAppsData, bindMountAppStorageDirs,
                         new String[]{PROC_START_SEQ_IDENT + app.getStartSeq()});
+                // By now the process group should have been created by zygote.
+                app.mProcessGroupCreated = true;
             }
 
             if (!regularZygote) {
                 // webview and app zygote don't have the permission to create the nodes
-                final int res = Process.createProcessGroup(uid, startResult.pid);
+                synchronized (app) {
-                if (res < 0) {
+                    if (!app.mSkipProcessGroupCreation) {
-                    if (res == -OsConstants.ESRCH) {
+                        // If we're not told to skip the process group creation, go create it.
-                        Slog.e(ActivityManagerService.TAG, "Unable to create process group for "
+                        final int res = Process.createProcessGroup(uid, startResult.pid);
-                            + app.processName + " (" + startResult.pid + ")");
+                        if (res < 0) {
-                    } else {
+                            if (res == -OsConstants.ESRCH) {
-                        throw new AssertionError("Unable to create process group for "
+                                Slog.e(ActivityManagerService.TAG,
-                            + app.processName + " (" + startResult.pid + ")");
+                                        "Unable to create process group for "
+                                        + app.processName + " (" + startResult.pid + ")");
+                            } else {
+                                throw new AssertionError("Unable to create process group for "
+                                    + app.processName + " (" + startResult.pid + ")");
+                            }
+                        } else {
+                            app.mProcessGroupCreated = true;
+                        }
                     }
                 }
             }

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

@@ -424,6 +424,16 @@ class ProcessRecord implements WindowProcessListener {
      */
     Runnable mSuccessorStartRunnable;
 
+    /**
+     * Whether or not the process group of this process has been created.
+     */
+    volatile boolean mProcessGroupCreated;
+
+    /**
+     * Whether or not we should skip the process group creation.
+     */
+    volatile boolean mSkipProcessGroupCreation;
+
     void setStartParams(int startUid, HostingRecord hostingRecord, String seInfo,
             long startUptime, long startElapsedTime) {
         this.mStartUid = startUid;
@@ -1192,8 +1202,26 @@ class ProcessRecord implements WindowProcessListener {
                 EventLog.writeEvent(EventLogTags.AM_KILL,
                         userId, mPid, processName, mState.getSetAdj(), reason);
                 Process.killProcessQuiet(mPid);
-                if (!asyncKPG) Process.sendSignalToProcessGroup(uid, mPid, OsConstants.SIGKILL);
+                final boolean killProcessGroup;
-                ProcessList.killProcessGroup(uid, mPid);
+                if (mHostingRecord != null
+                        && (mHostingRecord.usesWebviewZygote() || mHostingRecord.usesAppZygote())) {
+                    synchronized (ProcessRecord.this) {
+                        killProcessGroup = mProcessGroupCreated;
+                        if (!killProcessGroup) {
+                            // The process group hasn't been created, request to skip it.
+                            mSkipProcessGroupCreation = true;
+                        }
+                    }
+                } else {
+                    killProcessGroup = true;
+                }
+                if (killProcessGroup) {
+                    if (asyncKPG) {
+                        ProcessList.killProcessGroup(uid, mPid);
+                    } else {
+                        Process.sendSignalToProcessGroup(uid, mPid, OsConstants.SIGKILL);
+                    }
+                }
             } else {
                 mPendingStart = false;
             }