diff --git a/tools/valgrind/tsan/suppressions.txt b/tools/valgrind/tsan/suppressions.txt
index b231b4a51e658c999f0ccb12b499abe1e3dede14..d4f54dddf91774badb9352c8df4360c7228a8993 100644
--- a/tools/valgrind/tsan/suppressions.txt
+++ b/tools/valgrind/tsan/suppressions.txt
@@ -147,7 +147,7 @@
 }
 
 {
-  bug_61585
+  bug_61585a
   ThreadSanitizer:UnlockForeign
   fun:pthread_mutex_destroy
   ...
@@ -156,6 +156,18 @@
   fun:*AtExitManager*
 }
 
+{
+  bug_61585b
+  ThreadSanitizer:UnlockNonLocked
+  fun:pthread_mutex_unlock
+  fun:PR_Unlock
+  fun:nssSession_ExitMonitor
+  fun:find_objects
+  ...
+  fun:nssTrustDomain_FindCertificatesBySubject
+  ...
+}
+
 {
   bug_61753
   ThreadSanitizer:Race