GnuPG 2.1.14, file sm/call-agent.c

Many functions contain this declaration:

  struct default_inq_parm_s inq_parm = { ctrl, agent_ctx };

And later these statements:

  rc = start_agent (ctrl);
  if (rc)
    return rc;

When the agent is not already started, the initialization of inq_parm is done
too early because agent_ctx is NULL at that time.

agent_ctx becomes non-NULL in start_agent(), but this non-NULL value is not
copied to inq_parm->ctx.

(This causes effects like not being able to import a PKCS#12 file with
pinentry-mode=loopback if the agent has not been started before.)

Fix:

Each time you see the lines above, add this line after the »return rc;«:

  inq_parm->ctx = agent_ctx;

Thank you.