Merge branch 'maint'

* maint:
  History.md: fix a typo
  x509cert, x509crl, x509req, ns_spki: check sanity of public key
  pkey: make pkey_check_public_key() non-static
  test/test_cipher: fix test_non_aead_cipher_set_auth_data failure
  cipher: disallow setting AAD for non-AEAD ciphers
  test/test_ssl_session: skip tests for session_remove_cb
  appveyor.yml: remove 'openssl version' line

1 files changed, 4 insertions, 0 deletions

diff --git a/ext/openssl/ossl_ssl.c b/ext/openssl/ossl_ssl.c
index 63bdc9ab..8cdb9737 100644
--- a/ext/openssl/ossl_ssl.c
+++ b/ext/openssl/ossl_ssl.c
@@ -2595,6 +2595,10 @@ Init_ossl_ssl(void)
      * A callback invoked when a session is removed from the internal cache.
      *
      * The callback is invoked with an SSLContext and a Session.
+     *
+     * IMPORTANT NOTE: It is currently not possible to use this safely in a
+     * multi-threaded application. The callback is called inside a global lock
+     * and it can randomly cause deadlock on Ruby thread switching.
      */
     rb_attr(cSSLContext, rb_intern("session_remove_cb"), 1, 1, Qfalse);