Patch-Source: https://github.com/erlang/otp/pull/7450
https://github.com/erlang/otp/issues/7436
--
From fae85c2e38795c4d681ca010fb28a559c21375df Mon Sep 17 00:00:00 2001
From: Sverker Eriksson <sverker@erlang.org>
Date: Wed, 28 Jun 2023 15:52:30 +0200
Subject: [PATCH] crypto: Fix segv crash after purge-reload of crypto on musl

Symptom: Different kind of segv crashes after crypto is loaded,
purged and loaded again.

Problem:
dlclose on musl libc is a no-op.

Mutex 'mtx_init_curve_types' was destroyed at unload and then not
re-created at reload as static variable `library_initialized`
in crypto.c is true because musl dlclose is a no-op and dlopen
reuses the existing loaded crypto.so library with static variables
intact.
---
 lib/crypto/c_src/algorithms.c | 17 ++++++++++++++---
 lib/crypto/c_src/algorithms.h |  3 ++-
 lib/crypto/c_src/crypto.c     |  4 +++-
 3 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/lib/crypto/c_src/algorithms.c b/lib/crypto/c_src/algorithms.c
index 53b574af3aff..188b6c30a124 100644
--- a/lib/crypto/c_src/algorithms.c
+++ b/lib/crypto/c_src/algorithms.c
@@ -51,7 +51,6 @@ void init_rsa_opts_types(ErlNifEnv* env);
 
 void init_algorithms_types(ErlNifEnv* env)
 {
-    mtx_init_curve_types =  enif_mutex_create("init_curve_types");
 #ifdef HAS_3_0_API
 #else
     init_hash_types(env);
@@ -62,9 +61,21 @@ void init_algorithms_types(ErlNifEnv* env)
     /* ciphers and macs are initiated statically */
 }
 
-void cleanup_algorithms_types(ErlNifEnv* env)
+
+int create_curve_mutex(void)
+{
+    if (!mtx_init_curve_types) {
+        mtx_init_curve_types =  enif_mutex_create("init_curve_types");
+    }
+    return !!mtx_init_curve_types;
+}
+
+void destroy_curve_mutex(void)
 {
-    enif_mutex_destroy(mtx_init_curve_types);
+    if (mtx_init_curve_types) {
+        enif_mutex_destroy(mtx_init_curve_types);
+        mtx_init_curve_types = NULL;
+    }
 }
 
 /*================================================================
diff --git a/lib/crypto/c_src/algorithms.h b/lib/crypto/c_src/algorithms.h
index 25e1db129955..3c22a9fccc42 100644
--- a/lib/crypto/c_src/algorithms.h
+++ b/lib/crypto/c_src/algorithms.h
@@ -23,8 +23,9 @@
 
 #include "common.h"
 
+int create_curve_mutex(void);
+void destroy_curve_mutex(void);
 void init_algorithms_types(ErlNifEnv* env);
-void cleanup_algorithms_types(ErlNifEnv* env);
 
 ERL_NIF_TERM hash_algorithms(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
 ERL_NIF_TERM pubkey_algorithms(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
diff --git a/lib/crypto/c_src/crypto.c b/lib/crypto/c_src/crypto.c
index a21e9aaf204c..f1ccacfbac79 100644
--- a/lib/crypto/c_src/crypto.c
+++ b/lib/crypto/c_src/crypto.c
@@ -214,6 +214,8 @@ static int initialize(ErlNifEnv* env, ERL_NIF_TERM load_info)
     if (!create_engine_mutex(env)) {
         return __LINE__;
     }
+    if (!create_curve_mutex())
+        return __LINE__;
 
 #ifdef HAS_3_0_API
     prov_cnt = 0;
@@ -329,7 +331,7 @@ static int upgrade(ErlNifEnv* env, void** priv_data, void** old_priv_data,
 static void unload(ErlNifEnv* env, void* priv_data)
 {
     if (--library_refc == 0) {
-        cleanup_algorithms_types(env);
+        destroy_curve_mutex();
         destroy_engine_mutex(env);
     }