id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	uname	nginx_version
1706	Orphan processes after fatal signals	jiazhouyang09@…		"Hi,

I'm a PhD student, and I'm studying how software handles signals.

I found Nginx would have orphan processes when issued some fatal signals (including SIGILL, SIGABRT, SIGBUG, SIGFPE, SIGSEGV) to the main process. These signals might be triggered by some unknown bugs. In this case, Nginx could neither start nor stop:

$ sudo nginx
nginx: [emerg] bind() to *ip*:80 failed (98: Address already in use)

$ sudo nginx -s quit
nginx: [alert] kill(*pid*, 3) failed (3: No such process)

Also, any web server using the same port will fail to start. To fix this, users have to kill the orphan processes manually. 

I'm not sure if this is a bug. But I think it will be better if Nginx can exit gracefully. At least, do not corrupt the operating system.

Best,
Zhouyang"	defect	closed	minor		other		invalid			Linux ubuntu 4.13.0-39-generic #44~16.04.1-Ubuntu SMP Thu Apr 5 16:43:10 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux	"nginx version: nginx/1.14.0 (Ubuntu)
built with OpenSSL 1.1.0g  2 Nov 2017
TLS SNI support enabled
configure arguments: --with-cc-opt='-g -O2 -fdebug-prefix-map=/build/nginx-mcUg8N/nginx-1.14.0=. -fstack-protector-strong -Wformat -Werror=format-security -fPIC -Wdate-time -D_FORTIFY_SOURCE=2' --with-ld-opt='-Wl,-Bsymbolic-functions -Wl,-z,relro -Wl,-z,now -fPIC' --prefix=/usr/share/nginx --conf-path=/etc/nginx/nginx.conf --http-log-path=/var/log/nginx/access.log --error-log-path=/var/log/nginx/error.log --lock-path=/var/lock/nginx.lock --pid-path=/run/nginx.pid --modules-path=/usr/lib/nginx/modules --http-client-body-temp-path=/var/lib/nginx/body --http-fastcgi-temp-path=/var/lib/nginx/fastcgi --http-proxy-temp-path=/var/lib/nginx/proxy --http-scgi-temp-path=/var/lib/nginx/scgi --http-uwsgi-temp-path=/var/lib/nginx/uwsgi --with-debug --with-pcre-jit --with-http_ssl_module --with-http_stub_status_module --with-http_realip_module --with-http_auth_request_module --with-http_v2_module --with-http_dav_module --with-http_slice_module --with-threads --with-http_addition_module --with-http_geoip_module=dynamic --with-http_gunzip_module --with-http_gzip_static_module --with-http_image_filter_module=dynamic --with-http_sub_module --with-http_xslt_module=dynamic --with-stream=dynamic --with-stream_ssl_module --with-mail=dynamic --with-mail_ssl_module"