diff --git a/src/proto.h b/src/proto.h
index 24ad39a0..857a6794 100644
--- a/src/proto.h
+++ b/src/proto.h
@@ -68,7 +68,7 @@ enum {
 };
 MDBX_INTERNAL int txn_end(MDBX_txn *txn, unsigned mode);
 MDBX_INTERNAL int txn_write(MDBX_txn *txn, iov_ctx_t *ctx);
-MDBX_INTERNAL void txn_take_gcprof(MDBX_txn *txn, MDBX_commit_latency *latency);
+MDBX_INTERNAL void txn_take_gcprof(const MDBX_txn *txn, MDBX_commit_latency *latency);
 MDBX_INTERNAL void txn_merge(MDBX_txn *const parent, MDBX_txn *const txn, const size_t parent_retired_len);
 
 /* env.c */
diff --git a/src/txn.c b/src/txn.c
index 42203580..db3af6ed 100644
--- a/src/txn.c
+++ b/src/txn.c
@@ -395,7 +395,7 @@ void txn_merge(MDBX_txn *const parent, MDBX_txn *const txn, const size_t parent_
   }
 }
 
-void txn_take_gcprof(MDBX_txn *txn, MDBX_commit_latency *latency) {
+void txn_take_gcprof(const MDBX_txn *txn, MDBX_commit_latency *latency) {
   MDBX_env *const env = txn->env;
   if (MDBX_ENABLE_PROFGC) {
     pgop_stat_t *const ptr = &env->lck->pgops;