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samba-mirror/selftest
Stefan Metzmacher bc16a8abe3 lib/tsocket: avoid endless cpu-spinning in tstream_bsd_fde_handler()
There were some reports that strace output an LDAP server socket is in
CLOSE_WAIT state, returning EAGAIN for writev over and over (after a call to
epoll() each time).

In the tstream_bsd code the problem happens when we have a pending
writev_send, while there's no readv_send pending. In that case
we still ask for TEVENT_FD_READ in order to notice connection errors
early, so we try to call writev even if the socket doesn't report TEVENT_FD_WRITE.
And there are situations where we do that over and over again.

It happens like this with a Linux kernel:

    tcp_fin() has this:
        struct tcp_sock *tp = tcp_sk(sk);

        inet_csk_schedule_ack(sk);

        sk->sk_shutdown |= RCV_SHUTDOWN;
        sock_set_flag(sk, SOCK_DONE);

        switch (sk->sk_state) {
        case TCP_SYN_RECV:
        case TCP_ESTABLISHED:
                /* Move to CLOSE_WAIT */
                tcp_set_state(sk, TCP_CLOSE_WAIT);
                inet_csk_enter_pingpong_mode(sk);
                break;

It means RCV_SHUTDOWN gets set as well as TCP_CLOSE_WAIT, but
sk->sk_err is not changed to indicate an error.

    tcp_sendmsg_locked has this:
    ...
        err = -EPIPE;
        if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
                goto do_error;

        while (msg_data_left(msg)) {
                int copy = 0;

                skb = tcp_write_queue_tail(sk);
                if (skb)
                        copy = size_goal - skb->len;

                if (copy <= 0 || !tcp_skb_can_collapse_to(skb)) {
                        bool first_skb;

    new_segment:
                        if (!sk_stream_memory_free(sk))
                                goto wait_for_space;

    ...

    wait_for_space:
                set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
                if (copied)
                        tcp_push(sk, flags & ~MSG_MORE, mss_now,
                                 TCP_NAGLE_PUSH, size_goal);

                err = sk_stream_wait_memory(sk, &timeo);
                if (err != 0)
                        goto do_error;

It means if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN)) doesn't
hit as we only have RCV_SHUTDOWN and sk_stream_wait_memory returns
-EAGAIN.

    tcp_poll has this:

        if (sk->sk_shutdown & RCV_SHUTDOWN)
                mask |= EPOLLIN | EPOLLRDNORM | EPOLLRDHUP;

So we'll get EPOLLIN | EPOLLRDNORM | EPOLLRDHUP triggering
TEVENT_FD_READ and writev/sendmsg keeps getting EAGAIN.

So we need to always clear TEVENT_FD_READ if we don't
have readable handler in order to avoid burning cpu.
But we turn it on again after a timeout of 1 second
in order to monitor the error state of the connection.

And now that our tsocket_bsd_error() helper checks for POLLRDHUP,
we can check if the socket is in an error state before calling the
writable handler when TEVENT_FD_READ was reported.
Only on error we'll call the writable handler, which will pick
the error without calling writev().

BUG: https://bugzilla.samba.org/show_bug.cgi?id=15202

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Ralph Boehme <slow@samba.org>
(cherry picked from commit e232ba946f)
2022-10-31 14:30:09 +00:00
..
flapping.d CVE-2021-20251 s4:dsdb: Make badPwdCount update atomic 2022-09-18 16:46:09 +00:00
gnupg selftest:gnupg: add a gpg key for Samba Selftest <selftest@samba.example.com> 2016-07-22 16:03:27 +02:00
knownfail.d lib/tsocket: avoid endless cpu-spinning in tstream_bsd_fde_handler() 2022-10-31 14:30:09 +00:00
manage-ca selftest/manage-ca: Add certificiate etc. for DC addcsmb1 2020-04-03 15:08:26 +00:00
ns selftest: use 10.53.57.0/8 instead of 127.0.0.1/8 2020-03-27 09:02:38 +00:00
target selftest: Enable "old Samba" mode regarding GET_ANC/GET_TGT 2022-10-07 08:45:15 +00:00
checkpassword_arg1.sh selftest: require SAMBA_CPS_ACCOUNT_NAME in checkpassword_arg1.sh 2019-02-11 07:43:32 +01:00
create_smb1_fail_skipfile.txt selftest: Create instructions for generating skip file entries 2020-04-03 15:08:33 +00:00
devel_env.sh selftest: Add python path for compiled python modules like ldb 2021-08-24 12:29:32 +00:00
filter-subunit python2 reduction: Merge remaining compat code into common 2020-10-02 14:49:36 +00:00
flapping selftest: Remove samba3.blackbox.smbclient_tar from flapping tests 2020-12-01 19:06:45 +00:00
format-subunit PY3: change shebang to python3 in misc dirs 2018-12-14 18:00:40 +01:00
format-subunit-json python: remove all 'from __future__ import print_function' 2021-04-28 03:43:34 +00:00
gdb_backtrace selftest/gdb_backtrace: remove duplicate assignment. 2021-06-10 01:17:52 +00:00
gdb_backtrace_test.c
gdb_run selftest/gdb_*: make use of 'mktemp' 2016-12-01 05:54:21 +01:00
in_screen s3:rpc_server: Activate samba-dcerpcd 2021-12-10 14:02:30 +00:00
knownfail smbd: implement access checks for SMB2-GETINFO as per MS-SMB2 3.3.5.20.1 2022-09-06 07:54:14 +00:00
knownfail_heimdal_kdc CVE-2021-20251 s4:kdc: Check badPwdCount update return status 2022-09-18 16:46:09 +00:00
knownfail_mit_kdc CVE-2021-20251 s4-auth: Pass through error code from badPwdCount update 2022-09-18 16:46:09 +00:00
no-python-tests.txt selftest: Add basic sanity-check tests for nopython target 2019-02-20 02:10:00 +01:00
perf_tests.py perf_tests: Implicit string concatenation 2021-06-17 04:21:30 +00:00
quick selftest/quick: add smb2.session 2022-02-13 09:11:16 +00:00
README
save.env.sh selftest: add save.env.sh helper script. 2016-06-27 05:00:15 +02:00
selftest.pl CVE-2020-25719 CVE-2020-25717: selftest: remove "gensec:require_pac" settings 2021-11-09 19:45:32 +00:00
selftest.pl.1
selftesthelpers.py selftest: Fix setting environ for plansmbtorture4testsuite() 2021-08-03 09:28:38 +00:00
skip selftest: Remove skip of samba4.rpc.unixinfo 2021-08-31 00:12:53 +00:00
skip_mit_kdc selftest: add python S4U2Self tests including unkeyed checksums 2020-05-15 12:25:40 +00:00
skip.no-GSS_KRB5_CRED_NO_CI_FLAGS_X script/autobuild.py: try make test TESTS=samba3.*ktest for samba-systemkrb5 2017-01-10 13:54:17 +01:00
skip.opath-required s3: smbd: Fix openat_pathref_fsp() to cope with FIFO's in the filesystem. 2021-09-06 09:51:54 +00:00
slow
slow-none selftest: Move some more tests from the samba-o3 job 2020-10-01 01:18:38 +00:00
SocketWrapper.pm selftest: enable perl warnings 2020-02-04 05:13:39 +00:00
Subunit.pm selftest: enable perl warnings 2020-02-04 05:13:39 +00:00
subunithelper.py python:subunit: Avoid misleading "Test was never started" error message 2021-06-11 08:38:34 +00:00
tap2subunit
tests.py lib/tsocket: Add tests for loop on EAGAIN 2022-10-31 14:30:08 +00:00
TODO
todo_smb2_tests_to_port.list s3: torture: Remove the wildcard unlink test code. 2021-12-09 18:06:35 +00:00
ubsan.supp HEIMDAL: move code from source4/heimdal* to third_party/heimdal* 2022-01-19 21:41:59 +00:00
valgrind_run
wscript s3:rpc_server: Activate samba-dcerpcd 2021-12-10 14:02:30 +00:00

# vim: ft=rst

This directory contains test scripts that are useful for running a
bunch of tests all at once.

There are two parts to this:

 * The test runner (selftest/selftest.pl)
 * The test formatter

selftest.pl simply outputs subunit, which can then be formatted or analyzed
by tools that understand the subunit protocol. One of these tools is
format-subunit, which is used by default as part of "make test".

Available testsuites
====================
The available testsuites are obtained from a script, usually
source{3,4}/selftest/tests.py. This script should for each testsuite output
the name of the test, the command to run and the environment that should be
provided. Use the included "plantest" function to generate the required output.

Testsuite behaviour
===================

Exit code
------------
The testsuites should exit with a non-zero exit code if at least one
test failed. Skipped tests should not influence the exit code.

Output format
-------------
Testsuites can simply use the exit code to indicate whether all of their
tests have succeeded or one or more have failed. It is also possible to
provide more granular information using the Subunit protocol.

This protocol works by writing simple messages to standard output. Any
messages that can not be interpreted by this protocol are considered comments
for the last announced test.

For a full description of the subunit protocol, see the README file in the subunit
repository at http://github.com/testing-cabal/subunit.

The following commands are Samba extensions to Subunit:

start-testsuite
~~~~~~~~~~~~~~~
start-testsuite: name

The testsuite name is used as prefix for all containing tests.

skip-testsuite
~~~~~~~~~~~~~~
skip-testsuite: name

Mark the testsuite with the specified name as skipped.

testsuite-success
~~~~~~~~~~~~~~~~~
testsuite-success: name

Indicate that the testsuite has succeeded successfully.

testsuite-fail
~~~~~~~~~~~~~~
testsuite-fail: name

Indicate that a testsuite has failed.

Environments
============
Tests often need to run against a server with particular things set up,
a "environment". This environment is provided by the test "target": Samba 3,
Samba 4 or Windows.

The environments are currently available include

 - none: No server set up, no variables set.
 - dc,s3dc: Domain controller set up. The following environment variables will
   be set:

     * USERNAME: Administrator user name
     * PASSWORD: Administrator password
     * DOMAIN: Domain name
     * REALM: Realm name
     * SERVER: DC host name
     * SERVER_IP: DC IPv4 address
     * SERVER_IPV6: DC IPv6 address
     * NETBIOSNAME: DC NetBIOS name
     * NETIOSALIAS: DC NetBIOS alias

 - member,s4member,s3member: Domain controller and member server that is joined to it set up. The
   following environment variables will be set:

     * USERNAME: Domain administrator user name
     * PASSWORD: Domain administrator password
     * DOMAIN: Domain name
     * REALM: Realm name
     * SERVER: Name of the member server

See Samba.pm, Samba3.pm and Samba4.pm for the full list.

Running tests
=============

To run all the tests use::

   make test

To run a quicker subset run::

   make quicktest

To run a specific test, use this syntax::

   make test TESTS=testname

for example::

   make test TESTS=samba4.BASE-DELETE