src/http/modules/ngx_http_limit_req_module.c:237: error: Integer Overflow L2
  ([0, +oo] - 1):unsigned64.

src/http/modules/ngx_http_limit_req_module.c:241:13: <LHS trace>
239.             ngx_shmtx_unlock(&ctx->shpool->mutex);
240. 
241.             ctx->node = NULL;
                 ^
242.         }
243. 

src/http/modules/ngx_http_limit_req_module.c:241:13: Assignment
239.             ngx_shmtx_unlock(&ctx->shpool->mutex);
240. 
241.             ctx->node = NULL;
                 ^
242.         }
243. 

src/http/modules/ngx_http_limit_req_module.c:235:13: Call
233.             }
234. 
235.             ngx_shmtx_lock(&ctx->shpool->mutex);
                 ^
236. 
237.             ctx->node->count--;

src/core/ngx_shmtx.c:69:1: Parameter `mtx->spin`
  67. 
  68. 
  69. void
      ^
  70. ngx_shmtx_lock(ngx_shmtx_t *mtx)
  71. {

src/http/modules/ngx_http_limit_req_module.c:237:13: Binary operation: ([0, +oo] - 1):unsigned64
235.             ngx_shmtx_lock(&ctx->shpool->mutex);
236. 
237.             ctx->node->count--;
                 ^
238. 
239.             ngx_shmtx_unlock(&ctx->shpool->mutex);
