From eb73b10e6433e4ed9719d91eec3eb5090d293d1e Mon Sep 17 00:00:00 2001
From: Jon Shallow <supjps-libcoap@jpshallow.com>
Date: Sat, 30 May 2026 12:13:42 +0100
Subject: [PATCH] oss-fuzz: Further support for running with threading support

---
 tests/oss-fuzz/block_check_target.c     | 4 ++++
 tests/oss-fuzz/coap_fuzz_helper.c       | 2 ++
 tests/oss-fuzz/network_message_target.c | 2 ++
 tests/oss-fuzz/oscore_decrypt_target.c  | 2 ++
 tests/oss-fuzz/persist_target.c         | 2 ++
 tests/oss-fuzz/ws_frame_target.c        | 2 ++
 6 files changed, 14 insertions(+)

diff --git a/tests/oss-fuzz/block_check_target.c b/tests/oss-fuzz/block_check_target.c
index 14fe4111..f3bb19ca 100644
--- a/tests/oss-fuzz/block_check_target.c
+++ b/tests/oss-fuzz/block_check_target.c
@@ -176,8 +176,10 @@ LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
                       coap_session_max_pdu_size(session));
   if (pdu) {
     coap_add_option(pdu, COAP_OPTION_URI_PATH, 4, (const uint8_t *)"test");
+    coap_lock_lock(return 0);
     coap_add_data_large_request_lkd(session, pdu, data_len, test_data, NULL,
                                     NULL);
+    coap_lock_unlock();
     coap_delete_pdu(pdu);
   }
 
@@ -201,7 +203,9 @@ LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
     token.s = token_buf;
 
     coap_cancel_observe(session, &token, COAP_MESSAGE_CON);
+    coap_lock_lock(return 0);
     coap_cancel_observe_lkd(session, &token, COAP_MESSAGE_CON);
+    coap_lock_unlock();
     coap_delete_pdu(pdu);
   }
 
diff --git a/tests/oss-fuzz/coap_fuzz_helper.c b/tests/oss-fuzz/coap_fuzz_helper.c
index 0f1fc273..ecf3b9b4 100644
--- a/tests/oss-fuzz/coap_fuzz_helper.c
+++ b/tests/oss-fuzz/coap_fuzz_helper.c
@@ -88,7 +88,9 @@ coap_fuzz_dispatch(coap_context_t *ctx, coap_session_t *session,
     uint8_t *copy = malloc(size);
     if (copy) {
       memcpy(copy, data, size);
+      coap_lock_lock(return);
       coap_handle_dgram(ctx, session, copy, size);
+      coap_lock_unlock();
       free(copy);
     }
   }
diff --git a/tests/oss-fuzz/network_message_target.c b/tests/oss-fuzz/network_message_target.c
index 0bb005b5..45c181ca 100644
--- a/tests/oss-fuzz/network_message_target.c
+++ b/tests/oss-fuzz/network_message_target.c
@@ -11,7 +11,9 @@ test_dgram_dispatch(coap_context_t *ctx, coap_session_t *session,
   }
 
   session->state = COAP_SESSION_STATE_ESTABLISHED;
+  coap_lock_lock(return);
   coap_handle_dgram(ctx, session, data, size);
+  coap_lock_unlock();
 }
 
 /* Test retransmission queue operations (coap_wait_ack, peek_next, pop_next) */
diff --git a/tests/oss-fuzz/oscore_decrypt_target.c b/tests/oss-fuzz/oscore_decrypt_target.c
index 083c7d81..e5cac26a 100644
--- a/tests/oss-fuzz/oscore_decrypt_target.c
+++ b/tests/oss-fuzz/oscore_decrypt_target.c
@@ -74,7 +74,9 @@ LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
             }
 
             /* Test OSCORE decryption */
+            coap_lock_lock(return 0);
             decrypted = coap_oscore_decrypt_pdu(session, pdu);
+            coap_lock_unlock();
             if (decrypted) {
               coap_show_pdu(COAP_LOG_ERR, decrypted);
               coap_delete_pdu(decrypted);
diff --git a/tests/oss-fuzz/persist_target.c b/tests/oss-fuzz/persist_target.c
index d29968cf..96494aac 100644
--- a/tests/oss-fuzz/persist_target.c
+++ b/tests/oss-fuzz/persist_target.c
@@ -146,7 +146,9 @@ LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
 
       if (data[1] & 0x01) {
         /* Delete the subscription and trigger the observe deleted callback */
+        coap_lock_lock(return 0);
         coap_delete_observer(res, sess, &pdu->actual_token);
+        coap_lock_unlock();
       }
     }
 
diff --git a/tests/oss-fuzz/ws_frame_target.c b/tests/oss-fuzz/ws_frame_target.c
index 4e9e993c..301cee68 100644
--- a/tests/oss-fuzz/ws_frame_target.c
+++ b/tests/oss-fuzz/ws_frame_target.c
@@ -91,7 +91,9 @@ ws_fuzz_drive_read(coap_session_t *session, uint8_t *scratch,
     if (g_cursor.pos >= g_cursor.size)
       return;
     size_t before = g_cursor.pos;
+    coap_lock_lock(return);
     ssize_t r = coap_ws_read(session, scratch, scratch_len);
+    coap_lock_unlock();
     if (r < 0)
       return;
     /* No forward progress and no bytes returned: avoid infinite spin. */