LTTng » LTTng-tools

With lttng-ust 2.3.2, lttng-tools 2.3.2 and userspace-rcu 0.8.3 on CentOS 6 built using "gcc (GCC) 4.4.7 20120313 (Red Hat 4.4.7-4)", if I ./configure lttng-tools with the flags --disable-static --disable-epoll, then lttng-sessiond -v produces some error messages at startup:

DEBUG1 [31030/31036]: Woken up but nothing in the UST command queue (in thread_dispatch_ust_registration() at main.c:1527)
Error: Unknown poll events 0 for sock 3
DEBUG1 [31030/31036]: Futex n to 1 wait done (in futex_nto1_wait() at futex.c:90)
DEBUG1 [31030/31038]: fd 19 of 3 added to pollfd (in compat_poll_add() at compat-poll.c:188)
DEBUG1 [31030/31038]: Apps with sock 19 added to poll set (in thread_manage_apps() at main.c:1311)
DEBUG1 [31030/31038]: Apps thread polling on 2 fds (in thread_manage_apps() at main.c:1248)
DEBUG1 [31030/31038]: fd 21 of 4 added to pollfd (in compat_poll_add() at compat-poll.c:188)
DEBUG1 [31030/31038]: Apps with sock 21 added to poll set (in thread_manage_apps() at main.c:1311)
DEBUG1 [31030/31038]: Apps thread polling on 3 fds (in thread_manage_apps() at main.c:1248)
DEBUG1 [31030/31036]: Futex n to 1 prepare done (in futex_nto1_prepare() at futex.c:75)
DEBUG1 [31030/31036]: Woken up but nothing in the UST command queue (in thread_dispatch_ust_registration() at main.c:1527)
DEBUG1 [31030/31039]: fd 20 of 3 added to pollfd (in compat_poll_add() at compat-poll.c:188)
DEBUG3 [31030/31039]: UST thread notify added sock 20 to pollset (in ust_thread_manage_notify() at ust-thread.c:131)
DEBUG3 [31030/31039]: [ust-thread] Manage notify polling on 2 fds (in ust_thread_manage_notify() at ust-thread.c:61)
Error: Unknown poll events 0 for sock 3
DEBUG1 [31030/31039]: fd 22 of 4 added to pollfd (in compat_poll_add() at compat-poll.c:188)
DEBUG3 [31030/31039]: UST thread notify added sock 22 to pollset (in ust_thread_manage_notify() at ust-thread.c:131)
Error: Unknown poll events 0 for sock 20
DEBUG3 [31030/31039]: [ust-thread] Manage notify polling on 3 fds (in ust_thread_manage_notify() at ust-thread.c:61)

and then, when issuing a command such as lttng enable-event --userspace --all or lttng add-context --userspace -t vpid -t vtid -t procname, an assertion failure is seen in the session daemon's output:

DEBUG1 [31030/31035]: Creating UST session (in create_ust_session() at main.c:2454)
DEBUG3 [31030/31035]: Created hashtable size 4 at 0x7f01cc003d80 of type 0 (in lttng_ht_new() at hashtable.c:112)
DEBUG3 [31030/31035]: Created hashtable size 4 at 0x7f01cc0041c0 of type 1 (in lttng_ht_new() at hashtable.c:112)
DEBUG3 [31030/31035]: Copying tracing session consumer output in UST session (in copy_session_consumer() at main.c:2404)
DEBUG3 [31030/31035]: Created hashtable size 4 at 0x7f01cc004600 of type 1 (in lttng_ht_new() at hashtable.c:112)
DEBUG3 [31030/31035]: Copy session consumer subdir /ust (in copy_session_consumer() at main.c:2422)
DEBUG1 [31030/31035]: Spawning consumerd (in spawn_consumerd() at main.c:2085)
lttng-sessiond: ht-cleanup.c:92: thread_ht_cleanup: Assertion `pollfd == ht_cleanup_pipe[0]' failed.
DEBUG1 [3397/3397]: Using 64-bit UST consumer at: /opt/lttng-tools-2.3.2-no-epoll/lib/lttng/libexec/lttng-consumerd (in spawn_consumerd() at main.c:2161)
Aborted (core dumped)

If I remove --disable-epoll from the configure command line, then no such errors or assertion failures are seen.

I had used --disable-epoll previously for CentOS 5 compatibility, as CentOS 5 does not have epoll_pwait().