Merge branch 'sverker/erts/nif-monitor-down-lock-conflict/erlangGH-8983…

…/OTP-19330' into maint-25 * sverker/erts/nif-monitor-down-lock-conflict/erlangGH-8983/OTP-19330: erts: Fix potential lock order conflict in NIF monitor down callbacks
garazdawi · Nov 13, 2024 · 49abab4 · 49abab4
2 parents dd606e6 + 520edad
commit 49abab4
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diff --git a/erts/emulator/beam/erl_process.c b/erts/emulator/beam/erl_process.c
@@ -13590,7 +13590,9 @@ erts_proc_exit_handle_monitor(ErtsMonitor *mon, void *vctxt, Sint reds)
             break;
         }
         case ERTS_MON_TYPE_RESOURCE:
+            erts_proc_unlock(c_p, ERTS_PROC_LOCK_MAIN);
             erts_fire_nif_monitor(mon);
+            erts_proc_lock(c_p, ERTS_PROC_LOCK_MAIN);
             mon = NULL;
             break;
         case ERTS_MON_TYPE_DIST_PORT:

diff --git a/erts/emulator/test/nif_SUITE_data/nif_SUITE.c b/erts/emulator/test/nif_SUITE_data/nif_SUITE.c
@@ -2855,6 +2855,16 @@ static void monitor_resource_down(ErlNifEnv* env, void* obj, ErlNifPid* pid,
     enif_send(env, &rsrc->receiver, msg_env, msg);
     if (msg_env)
         enif_free_env(msg_env);
+
+    /* OTP-19330 GH-8983:
+     * Verify calling enif_whereis_pid/port in down callback
+     * without lock order violation. */
+    {
+        ErlNifPid pid;
+        ErlNifPid port;
+        enif_whereis_pid(env, atom_null, &pid);
+        enif_whereis_port(env, atom_null, &port);
+    }
 }
 
 static ERL_NIF_TERM alloc_monitor_resource_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])