commit b07505993dd8b2f367cf3b630f6da186e4e8550d
Author: Ingo Franzki <ifranzki@linux.ibm.com>
Date:   Wed Feb 10 15:12:25 2021 +0100

    Avoid deadlock in dlclose() after a fork
    
    Calling dlclose() in a atfork handler may cause a deadlock.
    dlclose() may itself modify the atfork handler table to remove
    any fork handlers that the to be unloaded library has registered.
    Since the atfork handler table is currently locked when we are in
    an atfork handler, this would produce a deadlock.
    
    Skip the dlclose() if we are in an atfork handler to avoid the deadlock.
    
    Signed-off-by: Ingo Franzki <ifranzki@linux.ibm.com>

diff --git a/usr/lib/api/api_interface.c b/usr/lib/api/api_interface.c
index 3ccb6d41..f1ee9132 100644
--- a/usr/lib/api/api_interface.c
+++ b/usr/lib/api/api_interface.c
@@ -1516,7 +1516,15 @@ CK_RV C_Finalize(CK_VOID_PTR pReserved)
             }
         }
 
-        DL_UnLoad(sltp, slotID);
+        /*
+         * Calling dlclose() in a atfork handler may cause a deadlock.
+         * dlclose() may itself modify the atfork handler table to remove
+         * any fork handlers that the to be unloaded library has registered.
+         * Since the atfork handler table is currently locked when we are in
+         * an atfork handler, this would produce a deadlock.
+         */
+        if (!in_child_fork_initializer)
+            DL_UnLoad(sltp, slotID);
     }
 
     // Un register from Slot D