PIPE asserts

[Václav Bílek]

Hello

On high load we are geting asserts (and varnish restarts) like this:

varnishd[23515]: Child (7569) Panic message: Assert error in Tcheck(),
cache.h line 648:#012  Condition((t.e) != 0) not true.  thread =
(cache-worker)sp = 0x7f76c5875008 {#012  fd = 611, id = 611, xid =
778413112,#012  client = 62.141.2.8:56778,#012  step = STP_PIPE,#012
handling = pipe,#012  err_code = 400, err_reason = (null),#012  ws =
0x7f76c5875078 { #012    id = "sess",#012    {s,f,r,e} =
{0x7f76c5875808,,+40,(nil),+16384},#012  },#012    worker =
0x7f7694353be0 {#012    },#012    vcl = {#012      srcname = {#012
  "input",#012        "Default",#012      },#012    },#012},#012

We do not PIPE anything explicitly ... after a day of run we have tens
of passes in hundreds millions of requests.
Is there any way how to absolutely disable piping of requests?
What kind of requests is piped?

Is there anything I can do for debuging this?

Vaclav Bilek