id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	uname	nginx_version
410	Valgrind falsepositive with ngx_string length 0	markus-linnala.myopenid.com		"I modified http://mdounin.ru/hg/nginx-tests to use valgrind.

    ==10811== Conditional jump or move depends on uninitialised value(s)
    ==10811==    at 0x4A0941F: memcpy@@GLIBC_2.14 (mc_replace_strmem.c:653)
    ==10811==    by 0x4248A0: ngx_vslprintf (ngx_string.c:236)
    ==10811==    by 0x421138: ngx_log_error_core (ngx_log.c:119)
    ==10811==    by 0x44F4B2: ngx_http_output_filter (ngx_http_core_module.c:1966)
    ==10811==    by 0x4535F9: ngx_http_send_special (ngx_http_request.c:3280)
    ==10811==    by 0x465283: ngx_http_upstream_finalize_request (ngx_http_upstream.c:3604)
    ==10811==    by 0x465C9D: ngx_http_upstream_process_request (ngx_http_upstream.c:3200)
    ==10811==    by 0x465DF1: ngx_http_upstream_process_upstream (ngx_http_upstream.c:3131)
    ==10811==    by 0x4694CE: ngx_http_upstream_process_header (ngx_http_upstream.c:2532)
    ==10811==    by 0x46595C: ngx_http_upstream_handler (ngx_http_upstream.c:996)
    ==10811==    by 0x4411EE: ngx_epoll_process_events (ngx_epoll_module.c:691)
    ==10811==    by 0x437A61: ngx_process_events_and_timers (ngx_event.c:249)
    ==10811==

Version is 1.5.5.

Test was: http_try_files.t

Problem is that memcpy looks v->data before looking lenght of copy and v->data is unititialized. Memcpy does not do anything if length is zero and therefore this is falsepositive.

There is other traces leading to the warning, most of them are debug messages with zero length strings. To see this you need to have --with-debug."	defect	closed	minor		nginx-core	1.3.x	wontfix				"nginx version: nginx/1.5.5
"