Index: head/sys/compat/linuxkpi/common/src/linux_rcu.c
===================================================================
--- head/sys/compat/linuxkpi/common/src/linux_rcu.c
+++ head/sys/compat/linuxkpi/common/src/linux_rcu.c
@@ -298,14 +298,13 @@
 	    "linux_synchronize_rcu() can sleep");
 
 	td = curthread;
+	DROP_GIANT();
 
 	/*
 	 * Synchronizing RCU might change the CPU core this function
 	 * is running on. Save current values:
 	 */
 	thread_lock(td);
-
-	DROP_GIANT();
 
 	old_cpu = PCPU_GET(cpuid);
 	old_pinned = td->td_pinned;
Index: head/sys/kern/subr_epoch.c
===================================================================
--- head/sys/kern/subr_epoch.c
+++ head/sys/kern/subr_epoch.c
@@ -610,8 +610,8 @@
 	KASSERT(!in_epoch(epoch), ("epoch_wait_preempt() called in the middle "
 	    "of an epoch section of the same epoch"));
 #endif
-	thread_lock(td);
 	DROP_GIANT();
+	thread_lock(td);
 
 	old_cpu = PCPU_GET(cpuid);
 	old_pinned = td->td_pinned;