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spec/util_debug_spec.lua @ 11665:148075532021
net.server_epoll: Prevent stack overflow of opportunistic writes
net.http.files serving a big enough file on a fast enough connection
with opportunistic_writes enabled could trigger a stack overflow through
repeatedly serving more data that immediately gets sent, draining the
buffer and triggering more data to be sent. This also blocked the server
on a single task until completion or an error.
This change prevents nested opportunistic writes, which should prevent
the stack overflow, at the cost of reduced download speed, but this is
unlikely to be noticeable outside of Gbit networks. Speed at the cost of
blocking other processing is not worth it, especially with the risk of
stack overflow.
author | Kim Alvefur <zash@zash.se> |
---|---|
date | Sun, 11 Jul 2021 09:39:21 +0200 |
parent | 11177:37dc2a6144d1 |
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local dbg = require "util.debug"; describe("util.debug", function () describe("traceback()", function () it("works", function () local tb = dbg.traceback(); assert.is_string(tb); end); end); describe("get_traceback_table()", function () it("works", function () local count = 0; -- MUST stay in sync with the line numbers of these functions: local f1_defined, f3_defined = 43, 15; local function f3(f3_param) --luacheck: ignore 212/f3_param count = count + 1; for i = 1, 2 do local tb = dbg.get_traceback_table(i == 1 and coroutine.running() or nil, 0); assert.is_table(tb); --print(dbg.traceback(), "\n\n\n", require "util.serialization".serialize(tb, { fatal = false, unquoted = true})); local found_f1, found_f3; for _, frame in ipairs(tb) do if frame.info.linedefined == f1_defined then assert.equal(0, #frame.locals); assert.equal("f2", frame.upvalues[1].name); assert.equal("f1_upvalue", frame.upvalues[2].name); found_f1 = true; elseif frame.info.linedefined == f3_defined then assert.equal("f3_param", frame.locals[1].name); found_f3 = true; end end assert.is_true(found_f1); assert.is_true(found_f3); end end local function f2() local f2_local = "hello"; return f3(f2_local); end local f1_upvalue = "upvalue1"; local function f1() f2(f1_upvalue); end -- ok/err are caught and re-thrown so that -- busted gets to handle them in its own way local ok, err; local function hook() debug.sethook(); ok, err = pcall(f1); end -- Test the traceback is correct in various -- types of caller environments -- From a Lua hook debug.sethook(hook, "crl", 1); local a = string.sub("abcdef", 3, 4); assert.equal("cd", a); debug.sethook(); assert.equal(1, count); if not ok then error(err); end ok, err = nil, nil; -- From a signal handler (C hook) require "util.signal".signal("SIGUSR1", hook); require "util.signal".raise("SIGUSR1"); assert.equal(2, count); if not ok then error(err); end ok, err = nil, nil; -- Inside a coroutine local co = coroutine.create(function () hook(); end); coroutine.resume(co); if not ok then error(err); end assert.equal(3, count); end); end); end);