Index: sys/kern/sys_generic.c
===================================================================
--- sys/kern/sys_generic.c	(wersja 239974)
+++ sys/kern/sys_generic.c	(kopia robocza)
@@ -703,28 +703,39 @@
 {
 	struct file *fp;
 	struct filedesc *fdp;
-	int error;
-	int tmp;
+	int error, tmp, locked;
 
 	AUDIT_ARG_FD(fd);
 	AUDIT_ARG_CMD(com);
-	if ((error = fget(td, fd, CAP_IOCTL, &fp)) != 0)
-		return (error);
+
+	fdp = td->td_proc->p_fd;
+
+	switch (com) {
+	case FIONCLEX:
+	case FIOCLEX:
+		FILEDESC_XLOCK(fdp);
+		locked = 1;
+		break;
+	default:
+		locked = 0;
+		break;
+	}
+
+	if ((error = fget(td, fd, CAP_IOCTL, &fp)) != 0) {
+		fp = NULL;
+		goto out;
+	}
 	if ((fp->f_flag & (FREAD | FWRITE)) == 0) {
-		fdrop(fp, td);
-		return (EBADF);
+		error = EBADF;
+		goto out;
 	}
-	fdp = td->td_proc->p_fd;
+
 	switch (com) {
 	case FIONCLEX:
-		FILEDESC_XLOCK(fdp);
 		fdp->fd_ofileflags[fd] &= ~UF_EXCLOSE;
-		FILEDESC_XUNLOCK(fdp);
 		goto out;
 	case FIOCLEX:
-		FILEDESC_XLOCK(fdp);
 		fdp->fd_ofileflags[fd] |= UF_EXCLOSE;
-		FILEDESC_XUNLOCK(fdp);
 		goto out;
 	case FIONBIO:
 		if ((tmp = *(int *)data))
@@ -744,7 +755,10 @@
 
 	error = fo_ioctl(fp, com, data, td->td_ucred, td);
 out:
-	fdrop(fp, td);
+	if (locked)
+		FILEDESC_XUNLOCK(fdp);
+	if (fp != NULL)
+		fdrop(fp, td);
 	return (error);
 }