id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	uname	nginx_version
1876	Some access log variables leak memory on HTTP/2 client connections	Dylan Plecki		"When used in the HTTP `log_format` directive, variables such as `$server_port` and `$server_addr` cause a rapid increase of memory utilization in situations where a large number of requests are sent over a connection, most notably with HTTP/2. The memory usage seems to be tied to the client connection, since closing the connection brings the memory usage back down.

I believe this may be caused by `ngx_pnalloc` calls within these variable methods, which allocate memory in the connection's memory pool, but do not free it until the connection is destroyed (see `ngx_http_variable_server_port` in `src/http/ngx_http_variables.c:1364` as an example). This does not pass muster under HTTP/2, which may keep client connections open indefinitely while multiplexing many requests.

Reproduction files will be attached in a tar file. Please see the `README.txt` file for repro steps.

This bug was found in an environment where nginx was used as a second-line proxy, behind another proxy that forwards all external requests over a small number of HTTP/2 connections to nginx. The memory leak was fast enough to exhaust 8GB of memory within 24 hours, while only processing a few hundred requests per second."	defect	closed	major		nginx-core	1.17.x	invalid	access_log memory leak		Linux 6692e65482cc 4.9.184-linuxkit #1 SMP Tue Jul 2 22:58:16 UTC 2019 x86_64 GNU/Linux	nginx version: nginx/1.17.4