diff --git a/msgr_receive.cpp b/msgr_receive.cpp
index e359e2d1..54c62953 100644
--- a/msgr_receive.cpp
+++ b/msgr_receive.cpp
@@ -9,6 +9,10 @@ void osd_messenger_t::read_requests()
     {
         int peer_fd = read_ready_clients[i];
         osd_client_t *cl = clients[peer_fd];
+        if (cl->read_msg.msg_iovlen)
+        {
+            continue;
+        }
         if (cl->read_remaining < receive_buffer_size)
         {
             cl->read_iov.iov_base = cl->in_buf;
@@ -29,6 +33,7 @@ void osd_messenger_t::read_requests()
             io_uring_sqe* sqe = ringloop->get_sqe();
             if (!sqe)
             {
+                cl->read_msg.msg_iovlen = 0;
                 read_ready_clients.erase(read_ready_clients.begin(), read_ready_clients.begin() + i);
                 return;
             }
@@ -52,6 +57,7 @@ void osd_messenger_t::read_requests()
 bool osd_messenger_t::handle_read(int result, osd_client_t *cl)
 {
     bool ret = false;
+    cl->read_msg.msg_iovlen = 0;
     cl->refs--;
     if (cl->peer_state == PEER_STOPPED)
     {
@@ -160,8 +166,14 @@ bool osd_messenger_t::handle_finished_read(osd_client_t *cl)
     {
         if (cl->read_op->req.hdr.magic == SECONDARY_OSD_REPLY_MAGIC)
             return handle_reply_hdr(cl);
-        else
+        else if (cl->read_op->req.hdr.magic == SECONDARY_OSD_OP_MAGIC)
             handle_op_hdr(cl);
+        else
+        {
+            printf("Received garbage: magic=%lx id=%lu opcode=%lx from %d\n", cl->read_op->req.hdr.magic, cl->read_op->req.hdr.id, cl->read_op->req.hdr.opcode, cl->peer_fd);
+            stop_client(cl->peer_fd);
+            return false;
+        }
     }
     else if (cl->read_state == CL_READ_DATA)
     {
diff --git a/msgr_send.cpp b/msgr_send.cpp
index 8542cb88..4fa44b99 100644
--- a/msgr_send.cpp
+++ b/msgr_send.cpp
@@ -46,7 +46,8 @@ void osd_messenger_t::outbox_push(osd_op_t *cur_op)
         to_send_list.push_back((iovec){ .iov_base = cur_op->req.buf, .iov_len = OSD_PACKET_SIZE });
         cl->sent_ops[cur_op->req.hdr.id] = cur_op;
     }
-    // Pre-defined send_lists
+    to_outbox.push_back(NULL);
+    // Operation data
     if ((cur_op->op_type == OSD_OP_IN
         ? (cur_op->req.hdr.opcode == OSD_OP_READ ||
         cur_op->req.hdr.opcode == OSD_OP_SEC_READ ||
@@ -58,17 +59,17 @@ void osd_messenger_t::outbox_push(osd_op_t *cur_op)
         cur_op->req.hdr.opcode == OSD_OP_SEC_STABILIZE ||
         cur_op->req.hdr.opcode == OSD_OP_SEC_ROLLBACK)) && cur_op->iov.count > 0)
     {
-        to_outbox.push_back(NULL);
         for (int i = 0; i < cur_op->iov.count; i++)
         {
             assert(cur_op->iov.buf[i].iov_base);
             to_send_list.push_back(cur_op->iov.buf[i]);
-            to_outbox.push_back(i == cur_op->iov.count-1 ? cur_op : NULL);
+            to_outbox.push_back(NULL);
         }
     }
-    else
+    if (cur_op->op_type == OSD_OP_IN)
     {
-        to_outbox.push_back(cur_op);
+        // To free it later
+        to_outbox[to_outbox.size()-1] = cur_op;
     }
     if (!ringloop)
     {
@@ -92,6 +93,10 @@ void osd_messenger_t::outbox_push(osd_op_t *cur_op)
 void osd_messenger_t::measure_exec(osd_op_t *cur_op)
 {
     // Measure execution latency
+    if (cur_op->req.hdr.opcode > OSD_OP_MAX)
+    {
+        return;
+    }
     timespec tv_end;
     clock_gettime(CLOCK_REALTIME, &tv_end);
     stats.op_stat_count[cur_op->req.hdr.opcode]++;
@@ -198,11 +203,8 @@ void osd_messenger_t::handle_send(int result, osd_client_t *cl)
             {
                 if (cl->outbox[done])
                 {
-                    // Operation fully sent
-                    if (cl->outbox[done]->op_type == OSD_OP_IN)
-                    {
-                        delete cl->outbox[done];
-                    }
+                    // Reply fully sent
+                    delete cl->outbox[done];
                 }
                 result -= iov.iov_len;
                 done++;
diff --git a/osd_primary.cpp b/osd_primary.cpp
index bdfb1f99..dd257d2b 100644
--- a/osd_primary.cpp
+++ b/osd_primary.cpp
@@ -489,7 +489,11 @@ resume_7:
         }
         // Remember PG as dirty to drop the connection when PG goes offline
         // (this is required because of the "lazy sync")
-        c_cli.clients[cur_op->peer_fd]->dirty_pgs.insert({ .pool_id = pg.pool_id, .pg_num = pg.pg_num });
+        auto cl_it = c_cli.clients.find(cur_op->peer_fd);
+        if (cl_it != c_cli.clients.end())
+        {
+            cl_it->second->dirty_pgs.insert({ .pool_id = pg.pool_id, .pg_num = pg.pg_num });
+        }
         dirty_pgs.insert({ .pool_id = pg.pool_id, .pg_num = pg.pg_num });
     }
     return true;