id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	uname	nginx_version
539	On certain kernel version epoll_release_file() hangs. Suggest manually EPOLL_CTL_DEL before close()ing	Zhe Yang		"Hello,

On kernel 3.13.5 / 3.13.8, nginx often hangs in D state. It's wchan when it's hang is epoll_release_file(). Kernel calls epoll_release_file() if a fd is still being watched by epoll when it's close()ing.

It seems to be a kernel bug, and I've also filed a bug on kernel's bugzilla at https://bugzilla.kernel.org/show_bug.cgi?id=73711 . But I suggest to disable event/modules/ngx_epoll_module.c:540, because saving this kernel call before close() may not worth. It may also make the kernel busy locking the global epmutex, and in some situation (e.g. bug in kernel), crash the system."	enhancement	closed	major		nginx-core	1.4.x	wontfix	epoll del_connection		"Linux localhost 3.13.5-1-ARCH #1 SMP PREEMPT Wed Dec 4 21:45:42 CET 2013 x86_64 GNU/Linux
"	"nginx version: nginx/1.4.4
TLS SNI support enabled
configure arguments: --prefix=/etc/nginx --conf-path=/etc/nginx/nginx.conf --sbin-path=/usr/sbin/nginx --pid-path=/var/run/nginx.pid --lock-path=/var/lock/nginx.lock --user=nobody --group=nobody --http-log-path=/var/log/nginx/access.log --error-log-path=/var/log/nginx/error.log --http-client-body-temp-path=/var/lib/nginx/client-body --http-proxy-temp-path=/var/lib/nginx/proxy --http-fastcgi-temp-path=/var/lib/nginx/fastcgi --http-scgi-temp-path=/var/lib/nginx/scgi --http-uwsgi-temp-path=/var/lib/nginx/uwsgi --with-pcre-jit --with-file-aio --with-ipv6 --with-debug --with-http_geoip_module --with-http_gzip_static_module --with-http_realip_module --with-http_ssl_module --with-http_spdy_module --with-google_perftools_module --with-http_stub_status_module --add-module=../../../../src/ngx_modules/ngx_cache_purge --add-module=../../../../src/ngx_modules/ngx_devel_kit --add-module=../../../../src/ngx_modules/lua-nginx-module --add-module=../../../../src/ngx_modules/echo-nginx-module --add-module=../../../../src/ngx_modules/ngx_http_consistent_hash
"