kernel: print PID in addition to TID in task log messages

For multithreads processes, it is hard to read logs without knowing task pids.

And let's print a decimal return codeo for syscalls. A hex return code are
usefull for system calls that return addresses. For other syscalls, the decimal
form is more readable.

PiperOrigin-RevId: 400035449

pkg/sentry/kernel/task_log.go

@@ -191,9 +191,11 @@ const (
 //
 // Preconditions: The task's owning TaskSet.mu must be locked.
 func (t *Task) updateInfoLocked() {
-	// Use the task's TID in the root PID namespace for logging.
+	// Use the task's TID and PID in the root PID namespace for logging.
+	pid := t.tg.pidns.owner.Root.tgids[t.tg]
 	tid := t.tg.pidns.owner.Root.tids[t]
-	t.logPrefix.Store(fmt.Sprintf("[% 4d] ", tid))
+	t.logPrefix.Store(fmt.Sprintf("[% 4d:% 4d] ", pid, tid))
+
 	t.rebuildTraceContext(tid)
 }
 

pkg/sentry/strace/strace.go

@@ -610,9 +610,9 @@ func (i *SyscallInfo) printExit(t *kernel.Task, elapsed time.Duration, output []
 	if err == nil {
 		// Fill in the output after successful execution.
 		i.post(t, args, retval, output, LogMaximumSize)
-		rval = fmt.Sprintf("%#x (%v)", retval, elapsed)
+		rval = fmt.Sprintf("%d (%#x) (%v)", retval, retval, elapsed)
 	} else {
-		rval = fmt.Sprintf("%#x errno=%d (%s) (%v)", retval, errno, err, elapsed)
+		rval = fmt.Sprintf("%d (%#x) errno=%d (%s) (%v)", retval, retval, errno, err, elapsed)
 	}
 
 	switch len(output) {