diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index c2c86705e0..9de0e235dc 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2021-02-22  Simon Marchi  <simon.marchi@polymtl.ca>
+
+	* thread.c (add_thread_silent): Add assert.
+	(find_thread_ptid): Add assert.
+
 2021-02-22  Simon Marchi  <simon.marchi@polymtl.ca>
 
 	PR gdb/27435
diff --git a/gdb/thread.c b/gdb/thread.c
index 8210706721..3e7d6e14bf 100644
--- a/gdb/thread.c
+++ b/gdb/thread.c
@@ -246,6 +246,8 @@ new_thread (struct inferior *inf, ptid_t ptid)
 struct thread_info *
 add_thread_silent (process_stratum_target *targ, ptid_t ptid)
 {
+  gdb_assert (targ != nullptr);
+
   inferior *inf = find_inferior_ptid (targ, ptid);
 
   /* We may have an old thread with the same id in the thread list.
@@ -535,6 +537,8 @@ find_thread_ptid (process_stratum_target *targ, ptid_t ptid)
 struct thread_info *
 find_thread_ptid (inferior *inf, ptid_t ptid)
 {
+  gdb_assert (inf != nullptr);
+
   for (thread_info *tp : inf->non_exited_threads ())
     if (tp->ptid == ptid)
       return tp;