See the example scenario below: $ ./mach mochitest editor/libeditor/tests/test_bug439808.html --debugger=rr ###### ### Now running mochitest-plain. ###### Checking for orphan ssltunnel processes... ehsan 13937 2757 0 16:45 pts/3 00:00:00 /home/ehsan/moz/src.try/obj-ff-clang-plugin.noindex/dist/bin/ssltunnel /tmp/ssltunnelWyz8Po.cfg Checking for orphan xpcshell processes... ehsan 13926 2757 0 16:45 pts/3 00:00:00 /home/ehsan/moz/src.try/obj-ff-clang-plugin.noindex/dist/bin/xpcshell -g /home/ehsan/moz/src.try/obj-ff-clang-plugin.noindex/dist/bin -v 170 -f /home/ehsan/moz/src.try/obj-ff-clang-plugin.noindex/dist/bin/components/httpd.js -e const _PROFILE_PATH = '/tmp/tmpOpIykV.mozrunner'; const _SERVER_PORT = '8888'; const _SERVER_ADDR = '127.0.0.1'; const _TEST_PREFIX = undefined; const _DISPLAY_RESULTS = true; -f /home/ehsan/moz/src.try/obj-ff-clang-plugin.noindex/_tests/testing/mochitest/server.js SUITE-START | Running 1 tests dir: editor/libeditor/tests pk12util: PKCS12 IMPORT SUCCESSFUL MochitestServer : launching [u'/home/ehsan/moz/src.try/obj-ff-clang-plugin.noindex/dist/bin/xpcshell', '-g', u'/home/ehsan/moz/src.try/obj-ff-clang-plugin.noindex/dist/bin', '-v', '170', '-f', u'/home/ehsan/moz/src.try/obj-ff-clang-plugin.noindex/dist/bin/components/httpd.js', '-e', "const _PROFILE_PATH = '/tmp/tmpaSbEDp.mozrunner'; const _SERVER_PORT = '8888'; const _SERVER_ADDR = '127.0.0.1'; const _TEST_PREFIX = undefined; const _DISPLAY_RESULTS = true;", '-f', '/home/ehsan/moz/src.try/obj-ff-clang-plugin.noindex/_tests/testing/mochitest/server.js'] runtests.py | Server pid: 22470 runtests.py | Websocket server pid: 22473 runtests.py | SSL tunnel pid: 22477 failed to bind socket on port 4443: error -5982 Shutting down... [22470] WARNING: failed to bind socket: file /home/ehsan/moz/src.try/netwerk/base/nsServerSocket.cpp, line 361 !!! could not start server on port 8888: [Exception... "Component returned failure code: 0x804b0036 (NS_ERROR_SOCKET_ADDRESS_IN_USE) [nsIServerSocket.init]" nsresult: "0x804b0036 (NS_ERROR_SOCKET_ADDRESS_IN_USE)" location: "JS frame :: /home/ehsan/moz/src.try/obj-ff-clang-plugin.noindex/dist/bin/components/httpd.js :: _start :: line 550" data: no] $ ps aux | grep ssltunnel ehsan 13937 0.0 0.0 32324 11164 pts/3 Sl 16:45 0:00 /home/ehsan/moz/src.try/obj-ff-clang-plugin.noindex/dist/bin/ssltunnel /tmp/ssltunnelWyz8Po.cfg What has happened here is I have an ssltunnel process lying around from a previous run of mochitest. I always kill this manually and retry, and I have literally done this tens of thousands of times so far. It would really be nice if our tools assisted us here by figuring out if the port is held open by such a process we have opened before, and kill it if so and retry automatically.

See https://dxr.mozilla.org/mozilla-central/rev/ef9a0f01e4f68214f0ff8f4631783b8a0e075a82/testing/mochitest/runtests.py#1641. I believe the issue here is that the ppid is not 1, so it is not considered an orphan. As I recall, I put that check in because I was feeling uneasy about killing an ssltunnel (or xpcshell or whatever) that might be running for another job (running 2 tests in parallel?).

How can one run two tests in parallel? The second one is going to launch an ssltunnel which is going to try to bind to the port that the first one is listening to.

Good point! So, better to kill any ssltunnel or xpcshell found running at the start of the test run? I'll try that out...

This works well for me locally and does not seem to cause any trouble in automation: https://treeherder.mozilla.org/#/jobs?repo=try&revision=ed03b5a8c0cd6fe4d8d7597e6407e0974bc28a0e

Comment on attachment 8902323 [details] [diff] [review] kill any xpcshell or ssltunnel already running at start of mochitest or remote reftest Review of attachment 8902323 [details] [diff] [review]: ----------------------------------------------------------------- good stuff

Pushed by gbrown@mozilla.com: https://hg.mozilla.org/integration/mozilla-inbound/rev/b823779242ed Kill any xpcshell or ssltunnel already running at start of tests; r=jmaher

Thank you so much! If I say I may have spent days of my life overall hunting down these rouge ssltunnel processes and killing them manually, I don't think I'm overstating it. :-)