LTTng » LTTng-UST

When running the sample program or one of my programs, Valgrind reports the thread created in lttng_ust_init as leaked:

==19830== 320 bytes in 1 blocks are possibly lost in loss record 3 of 4
==19830==    at 0x4C279F2: calloc (vg_replace_malloc.c:467)
==19830==    by 0x4011874: _dl_allocate_tls (dl-tls.c:300)
==19830==    by 0x5E23B68: pthread_create@@GLIBC_2.2.5 (allocatestack.c:571)
==19830==    by 0x503A5E9: lttng_ust_init (lttng-ust-comm.c:907)
==19830==    by 0x400EB55: call_init.part.0 (dl-init.c:85)
==19830==    by 0x400EC2E: _dl_init (dl-init.c:52)
==19830==    by 0x40015E9: ??? (in /lib/x86_64-linux-gnu/ld-2.13.so)
==19830== 
==19830== 320 bytes in 1 blocks are possibly lost in loss record 4 of 4
==19830==    at 0x4C279F2: calloc (vg_replace_malloc.c:467)
==19830==    by 0x4011874: _dl_allocate_tls (dl-tls.c:300)
==19830==    by 0x5E23B68: pthread_create@@GLIBC_2.2.5 (allocatestack.c:571)
==19830==    by 0x503A613: lttng_ust_init (lttng-ust-comm.c:913)
==19830==    by 0x400EB55: call_init.part.0 (dl-init.c:85)
==19830==    by 0x400EC2E: _dl_init (dl-init.c:52)
==19830==    by 0x40015E9: ??? (in /lib/x86_64-linux-gnu/ld-2.13.so)

I have not been able to fix this problem. However, during the investigation of this problem, I noticed that the threads are being created in the default state but are never intended to be explicitly detached or joined. If pthread_detach or pthread_join is never called, the thread should be created with the PTHREAD_CREATE_DETACHED detach state so that their storage can be reclaimed when the thread terminates.

To be clear, this patch does not fix my problem with Valgrind, but it changes behavior to match the spec.