{ ZLib doesn't allocate its buffer. This is no bug according to the FAQ. Memcheck:Cond fun:longest_match fun:deflate_slow fun:deflate } { Not sure why this happens. Memcheck:Leak fun:calloc fun:_dl_allocate_tls fun:pthread_create@@GLIBC_2.1 fun:_ZN5boost6thread12start_threadEv } { Memcheck:Param socketcall.sendto(msg) fun:sendto fun:getaddrinfo } { Memcheck:Cond fun:BN_bin2bn } { Memcheck:Cond fun:BN_num_bits_word } { Memcheck:Value4 fun:BN_mod_exp_mont_consttime fun:BN_mod_exp_mont } { Memcheck:Value4 fun:BN_num_bits_word fun:BN_mod_exp_mont_consttime fun:BN_mod_exp_mont }