Re: [Valgrind-users] Probably OT: Losing memory within gethostbyname_r, inet_ntoa

[Crispin F. <cr...@th...>]

Hi,

> The other case is about inet_ntoa, which is supposed to reuse the same
> statically allocated buffer in subsequent requests. Yet I get multiple
> reports like this one:
> 
> ==23379== 200 bytes in 1 blocks are still reachable in loss record 9 of 12
> ==23379==    at 0x40244FF4: my_malloc (vg_libpthread.c:267)
> ==23379==    by 0x40246B41: get_or_allocate_specifics_ptr (vg_libpthread.c:1392)
> ==23379==    by 0x40246C56: __pthread_key_create (vg_libpthread.c:1429)
> ==23379==    by 0x40342DF1: init (in /lib/libc.so.6)
> ==23379==    by 0x40246E7C: __pthread_once (vg_libpthread.c:1514)
> ==23379==    by 0x40342D18: inet_ntoa (in /lib/libc.so.6)
> ==23379==    by 0x805F812: accept_connection (jbsockets.c:714)
> ==23379==    by 0x806204D: listen_loop (jcc.c:2252)
> ==23379==    by 0x8061D27: main (jcc.c:2072)
> ==23379==    by 0x402797ED: __libc_start_main (in /lib/libc.so.6)
> ==23379==    by 0x80496F0: (within /home/oes/projekte/privoxy/current/privoxy)
> 
> How and why does __pthread_once get called from within inet_ntoa and what
> does valgrind's vg_libpthread need 200 bytes for?

The code inside inet_ntoa uses the pthread_once function to initialise
its a pthread key, which allows it to store per-thread data. Valgrind
uses the 200 bytes to store the entries for each of the allocated
pthread keys for each thread. I wouldn't worry about this error at all,
from my reading, the worst you are likely to get is 200 bytes per
thread.

Crispin