GitHub user shinrich opened a pull request:
https://github.com/apache/trafficserver/pull/1375
Incorrectly freeing Http1ClientSession setting up to return a error
Saw a very deep stack. The following is the stop of the stack.
{code}
#0 0x in ?? ()
#1 0x005e05ab in Http1ClientTransaction::do_io_write
(this=0x2b512412e3d8, c=0x2b4ffd082470, nbytes=123, buf=0x2b50b4075e60,
owner=false) at Http1ClientTransaction.h:45
#2 0x0063c7f5 in HttpTunnel::producer_run (this=0x2b4ffd082470,
p=0x2b4ffd082670) at HttpTunnel.cc:916
#3 0x0063c103 in HttpTunnel::tunnel_run (this=0x2b4ffd082470,
p_arg=0x2b4ffd082670) at HttpTunnel.cc:734
#4 0x005ff225 in HttpSM::setup_internal_transfer
(this=0x2b4ffd080fd0, handler_arg=(int (HttpSM::)(HttpSM *, int, void *))
0x5f383c ) at HttpSM.cc:6222
#5 0x005ef6ae in HttpSM::handle_api_return (this=0x2b4ffd080fd0) at
HttpSM.cc:1721
#6 0x005ef30b in HttpSM::state_api_callout (this=0x2b4ffd080fd0,
event=6, data=0x0) at HttpSM.cc:1596
#7 0x005ee9e6 in HttpSM::state_api_callback (this=0x2b4ffd080fd0,
event=6, data=0x0) at HttpSM.cc:1394
#8 0x00534ea1 in TSHttpTxnReenable (txnp=0x2b4ffd080fd0,
event=TS_EVENT_HTTP_CONTINUE) at InkAPI.cc:5652
{code}
I spent some time grubbing through the core. It is interesting that the
whole transaction is on the stack. The Http1ClientSession gets created in frame
67. We crash because it has been deleted.
I think the problem is in frame 4 in HttpSM::setup_internal_transfer. This
is an error case. Specifically ATS is trying to return "HTTP/1.0 500 INKApi
Error\r\nDate: Wed, 18 May 2016 20:21:46 GMT\r\nConnection: close\r\nServer:
ATS/5.3.0\r\nContent-Length: 0\r\n\r\n" which gets set from
HttpTransact::HandleApiErrorJump.
But in setup_internal_transfer, we call tunnel.kill_tunnel to remove any
previous static producers. But if there was a previous tunnel setup with our
Http1ClientTransaction/Session as a consumer, it would call do_io_close on it
which would likely free the Http1ClientSession object.
Replaced the kill_tunnel with a reset which doesn't free the
consumer/producer. The crash went away.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/shinrich/trafficserver early-client-free
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/trafficserver/pull/1375.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #1375
commit 95010edee4c5378b4f1f46174100e7a6e6115d13
Author: Susan Hinrichs
Date: 2017-01-25T20:46:56Z
Incorrectly freeing Http1ClientSession while setting up to return a error
header.
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