System profile:

Ubuntu 12.04.5 LTS precise, kernel 3.9.3
lttng-modules-2.9.0-pre-17-152fe7f
userspace-rcu-0.10-pre-2-d8a4979
lttng-ust-2.9.0-pre-84-4c62d8d
lttng-tools-2.9.0-pre-258-36bc42d

Running a user-local lttng-sessiond from the command line (after shutting down the root service):

$ lttng-sessiond -vvv 2>&1 | tee lttng-sessiond.1b.log

So far so good.  I test the daemon with 'lttng list' from another shell.  But when I hit ctrl-c in the daemon's shell, it doesn't respond and the CPU usage goes crazy (~90%).  Can't sudo kill it either.

dmesg is utterly silent.

What is happening?

The log is available; here are the last few lines:

$ lttng-sessiond -vvv 2>&1 | tee lttng-sessiond.2.log
...
DEBUG3 - 09:53:51.873996 [3186/3189]: [ht-thread] Polling. (in thread_ht_cleanup() at ht-cleanup.c:124)
DEBUG3 - 09:53:51.874189 [3186/3186]: Session daemon client socket 14 and application socket 15 created (in init_daemon_socket() at main.c:5182)
DEBUG3 - 09:53:51.874203 [3186/3186]: Created hashtable size 4 at 0x1635110 of type 2 (in lttng_ht_new() at hashtable.c:145)
DEBUG3 - 09:53:51.874205 [3186/3186]: Global buffer per UID registry initialized (in buffer_reg_init_uid_registry() at buffer-registry.c:99)
...
DEBUG1 - 09:54:10.381606 [3186/3191]: Wait for client response (in thread_manage_clients() at main.c:4455)
DEBUG1 - 09:54:10.382236 [3186/3191]: Receiving data from client ... (in thread_manage_clients() at main.c:4500)
DEBUG1 - 09:54:10.383618 [3186/3191]: Processing client command 13 (in process_client_msg() at main.c:2984)
DEBUG1 - 09:54:10.383812 [3186/3191]: Counting number of available session for UID 1000 GID 1000 (in lttng_sessions_count() at main.c:2953)
DEBUG1 - 09:54:10.383923 [3186/3191]: Getting all available session for UID 1000 GID 1000 (in cmd_list_lttng_sessions() at cmd.c:3098)
DEBUG1 - 09:54:10.384067 [3186/3191]: Sending response (size: 20, retcode: Success (10)) (in thread_manage_clients() at main.c:4550)
DEBUG1 - 09:54:10.384221 [3186/3191]: Clean command context structure (in clean_command_ctx() at main.c:791)
DEBUG1 - 09:54:10.384330 [3186/3191]: Accepting client command ... (in thread_manage_clients() at main.c:4403)
^C

Daniel U. Thibault, M.Sc.²

Informaticien scientifique, CME-PSC, Centre de recherches de Valcartier
Recherche et développement pour la défense Canada / Gouvernement du Canada
daniel.thibault at drdc-rddc.gc.ca / Tél: 418-844-4000x4245 Téléc: 418-844-4538
daniel.thibault at forces.gc.ca / Tél: 418-844-4000x4245 Téléc: 418-844-4538

Computer Scientist, MCCS-SPC, Valcartier Research Centre 
Defence Research and Development Canada / Government of Canada
daniel.thibault at drdc-rddc.gc.ca / Tel: 418-844-4000x4245 Fax: 418-844-4538
daniel.thibault at forces.gc.ca / Tel: 418-844-4000x4245 Fax: 418-844-4538

DRDC is an agency of the Department of National Defence / RDDC est une agence du ministère de la Défense nationale