get_headers does not return when using http2 #202

Activity

1. Mehgugs commented on Jul 9, 2022

   

   Mehgugs

   on Jul 9, 2022

   ContributorAuthor

   More actions

   Okay so I think I've found part of the issue:

   In get_headers the connection polls but the self.connection:step(0) times out. Due to how step works this timeout is simply returned as true which means the get_headers loop goes into a blocking call again; which never seems to terminate unless timed out.

   When I catch the offending thread and inspect the locals I can grab the stream object. If I manually step the attached connection the poll returns and the deadlock is fixed.

   Here is an example which seems to reproduce the problem, it is not always reproduced which suggests to me it's some kind of race condition in the code.

   local request = require"http.request"
   local errno   = require"cqueues.errno"
   local loop    = require"cqueues".new()
   
   local DATA = [[{"hi" : "]] .. ("there"):rep(1000)..[["}]]
   
   local TIMEOUT = 10
   local VERSION = 2
   
   loop:wrap(function()
       local r = request.new_from_uri("https://postman-echo.com/post")
       r.headers:upsert(":method", "POST")
       r.headers:upsert("content-type", "application/json")
   
       r.version = VERSION
       r.expect_100_timeout = TIMEOUT 
   
       r:set_body(DATA)
   
       for hname, value, never_index in r.headers:each() do
           print(string.format("%s = %s", hname, never_index and "<never_index>" or value))
       end
   
       local headers , stream , eno = r:go(TIMEOUT)
   
       if not headers then
           print(string.format("%q (%s, %q)",
               tostring(stream), eno and errno[eno] or "?", eno and errno.strerror(eno) or "??"))
           return
       end
   
       print(headers:get":status")
   
   
   end)
   
   assert(loop:loop())

   If you set version to 1.1 the request completes.
   If you make body smaller the request completes.
   The request will often timeout with a small timeout; if you make the timeout large enough you receive the following:

   "PROTOCOL_ERROR(0x1): Protocol error detected: 'RST_STREAM' on stream #1 (code=0x1)" (?, "??")

   The request will also sometimes complete successfully.