id summary reporter owner description type status priority milestone component version resolution keywords cc uname nginx_version 2111 Worker dumps core with image_filter test, proxy and HTML response from upstream lordgurke@… "nginx worker process dumps core (and drops connection) if the following prerequisites are satisfied: - Use nginx as reverse proxy for URIs with Regex location - Enable caching - Configure a rewrite rule inside that location - Add ""image_filter test"" to location - Configure a PNG file as error page for error 415, i.e. - Request (GET) an URI through nginx, which leads to a 404 error on upstream, Upstream will send HTML content with correct content type ""text/html"" -- Requests shall be made with curl or wget - for unknown reasons that bug will not trigger when you use a browser like Firefox. Also, this will not work with ""HEAD"" requests! - Worker will core dump I have traced this down to the use of ""image_filter test"". This happens with HTTP/2 as well as with HTTP/1.1. If I enable ""proxy_intercept"" to deliver my custom error page, the problem does not occur. Example config: {{{ error_page 415 404 403 500 502 503 504 /errorpages/image-not-found.png location ~* /images/(.*).jpg$ { rewrite /images/(?(.*).jpg$ /media/get/$imgid break; image_filter test; proxy_pass ..... } }}} Request: {{{ curl -v 'https://domain/images/404.jpg' > /dev/null % Total % Received % Xferd Average Speed Time Time Time Current Dload Upload Total Spent Left Speed 39 83829 39 32768 0 0 11175 0 0:00:07 0:00:02 0:00:05 11172 curl: (18) transfer closed with 51061 bytes remaining to read }}} Upstream delivers a HTML response instead of an image: {{{ HTTP/1.1 404 Not Found Date: Fri, 18 Dec 2020 15:33:33 GMT Server: Apache Cache-Control: no-cache, private Transfer-Encoding: chunked Content-Type: text/html; charset=UTF-8 327 An Error Occurred: Not Found ....... }}} Log says: {{{ [alert] 50253#50253: worker process 50260 exited on signal 11 (core dumped) }}} Stack trace: {{{ #0 0x0000557821885ccc ngx_http_file_cache_update (nginx) #1 0x000055782187c2df ngx_http_upstream_process_request (nginx) #2 0x000055782187b662 ngx_http_upstream_handler (nginx) #3 0x00005578218543ae ngx_epoll_process_events (nginx) #4 0x000055782184a7da ngx_process_events_and_timers (nginx) #5 0x0000557821852639 ngx_worker_process_cycle (nginx) #6 0x0000557821850b2f ngx_spawn_process (nginx) #7 0x0000557821851cf0 ngx_start_worker_processes (nginx) #8 0x0000557821853007 ngx_master_process_cycle (nginx) #9 0x0000557821829a56 main (nginx) #10 0x00007f54d2d347b3 __libc_start_main (libc.so.6) #11 0x0000557821829abe _start (nginx) }}}" defect closed major nginx-module 1.19.x worksforme image_filter Linux xxxx 4.18.0-240.1.1.el8_3.x86_64 #1 SMP Thu Nov 19 17:20:08 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux "nginx version: nginx/1.18.0 built by gcc 8.3.1 20191121 (Red Hat 8.3.1-5) (GCC) built with OpenSSL 1.1.1c FIPS 28 May 2019 (running with OpenSSL 1.1.1g FIPS 21 Apr 2020) TLS SNI support enabled configure arguments: --prefix=/etc/nginx --sbin-path=/usr/sbin/nginx --modules-path=/usr/lib64/nginx/modules --conf-path=/etc/nginx/nginx.conf --error-log-path=/var/log/nginx/error.log --http-log-path=/var/log/nginx/access.log --pid-path=/var/run/nginx.pid --lock-path=/var/run/nginx.lock --http-client-body-temp-path=/var/cache/nginx/client_temp --http-proxy-temp-path=/var/cache/nginx/proxy_temp --http-fastcgi-temp-path=/var/cache/nginx/fastcgi_temp --http-uwsgi-temp-path=/var/cache/nginx/uwsgi_temp --http-scgi-temp-path=/var/cache/nginx/scgi_temp --user=nginx --group=nginx --with-compat --with-file-aio --with-threads --with-http_addition_module --with-http_auth_request_module --with-http_dav_module --with-http_flv_module --with-http_gunzip_module --with-http_gzip_static_module --with-http_mp4_module --with-http_random_index_module --with-http_realip_module --with-http_secure_link_module --with-http_slice_module --with-http_ssl_module --with-http_stub_status_module --with-http_sub_module --with-http_v2_module --with-mail --with-mail_ssl_module --with-stream --with-stream_realip_module --with-stream_ssl_module --with-stream_ssl_preread_module --with-cc-opt='-O2 -g -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -fexceptions -fstack-protector-strong -grecord-gcc-switches -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection -fPIC' --with-ld-opt='-Wl,-z,relro -Wl,-z,now -pie'"