yaoweibin
ajp_cache_path causes segmentation fault on Nginx 1.8.0
Using the latest version of this code, Nginx 1.8.0 seg faults on startup when the following is present within the configuration, noting this used to work with Nginx 1.6.3:
ajp_cache_path /var/cache/nginx/ajp_cache levels=1:2
keys_zone=ajp_cache:60m
inactive=100m;
Using gdb to get a backtrace shows:
Program received signal SIGSEGV, Segmentation fault.
ngx_array_push (a=0x0) at src/core/ngx_array.c:54
54 if (a->nelts == a->nalloc) {
(gdb) bt
#0 ngx_array_push (a=0x0) at src/core/ngx_array.c:54
#1 0x000000000045f907 in ngx_http_file_cache_set_slot (cf=0x7fffffffe0d0,
cmd=0x6fe450, conf=0x0) at src/http/ngx_http_file_cache.c:2432
#2 0x000000000041a486 in ngx_conf_handler (cf=0x7fffffffe0d0, filename=0x0)
at src/core/ngx_conf_file.c:391
#3 ngx_conf_parse (cf=0x7fffffffe0d0, filename=0x0)
at src/core/ngx_conf_file.c:247
#4 0x0000000000435c9a in ngx_http_block (cf=0x7fffffffe0d0,
cmd=<value optimized out>, conf=<value optimized out>)
at src/http/ngx_http.c:240
#5 0x000000000041a486 in ngx_conf_handler (cf=0x7fffffffe0d0,
filename=0x730f58) at src/core/ngx_conf_file.c:391
#6 ngx_conf_parse (cf=0x7fffffffe0d0, filename=0x730f58)
at src/core/ngx_conf_file.c:247
#7 0x0000000000417cf6 in ngx_init_cycle (old_cycle=0x7fffffffe180)
at src/core/ngx_cycle.c:264
#8 0x0000000000409196 in main (argc=<value optimized out>,
argv=<value optimized out>) at src/core/nginx.c:345
When you say 'latest version' do you mean latest git revision or released version? If you haven't been using git, could you try the latest revision (bf6cd93f2098b59260de8d494f0f4b1f11a84627)?
The latest from git at the time of my post, which is that revision. I had to double-check because of the commit message, indicating compatibility fixes.
Can you try this; Line 176, .. - key = ngx_array_push(&r->cache->keys); .. + key = ngx_array_push(&r->keys);
See also https://github.com/FRiCKLE/ngx_cache_purge/blob/master/ngx_cache_purge_module.c line 1381, a quick look, this looks similar to what ajp is doing. Or its a missing init via ngx_http_cache_t *c; (rc = ...)
@itpp16 That diff breaks compilation:
cc -c -pipe -O -W -Wall -Wpointer-arith -Wno-unused-parameter -Werror -g -O2 -g -I src/core -I src/event -I src/event/modules -I src/os/unix -I /root/rpmbuild/BUILD/nginx-1.8.0/nginx_ajp_module -I /usr/include/libxml2 -I objs -I src/http -I src/http/modules -I src/mail \
-o objs/addon/nginx_ajp_module/ngx_http_ajp_handler.o \
/root/rpmbuild/BUILD/nginx-1.8.0/nginx_ajp_module/ngx_http_ajp_handler.c
/root/rpmbuild/BUILD/nginx-1.8.0/nginx_ajp_module/ngx_http_ajp_handler.c: In function ‘ngx_http_ajp_create_key’:
/root/rpmbuild/BUILD/nginx-1.8.0/nginx_ajp_module/ngx_http_ajp_handler.c:176: error: ‘ngx_http_request_t’ has no member named ‘keys’
make[1]: *** [objs/addon/nginx_ajp_module/ngx_http_ajp_handler.o] Error 1
I don't know enough about the internals of Nginx to judge on the latter.
I know :( Still looking for a solution. Without the cache ajp does work fine.
I fixed this issue. Give it a fly, please give me the result. If there is no problem, then I will try pull request.
Latest commit: https://github.com/vozlt/nginx_ajp_module/commit/3b41fcc14381ec167bc610d33c8fdeed24734701 Branch: https://github.com/vozlt/nginx_ajp_module/tree/vozlt-patch-0
Good news is it works but during cache initialization (nginx startup) it crashes a worker, only once but still indicating some issue somewhere. I'll try to debug later, maybe https://github.com/davidjb can try and do a backtrace to see if its still happening at the ngx_array_push point.
Its not array_push, its crashing a worker when the cache manager is called to cleanup or refill the old cache, caching by itself is not working either. Still looking deeper to see whats going on.
@itpp16 any progress to report? sorry for ping, just very keen on hearing more about it.
No progress in debugging but I did made a workaround, please try this to see if this works for you:
http {
proxy_cache_path ajp_temp/ajp_cache levels=1:2 keys_zone=ajp_cache_zone:10m inactive=24h max_size=2m;
[...]
server {
listen 880;
[...]
location /ajptest1/ {
proxy_pass http://127.0.0.1:880/ajptest2/;
proxy_cache ajp_cache_zone;
proxy_cache_key "$host$request_uri$cookie_user";
proxy_cache_valid 200 1d;
proxy_cache_use_stale error timeout invalid_header updating http_500;
add_header X-Cache $upstream_cache_status;
}
location /ajptest2/ {
rewrite /ajptest2/([^/]+) /$1 break;
ajp_pass tomcats/;
}
It's basically a local loop using default caching, tested here and works fine.
Hi! still always open the issue.. I have the same segmentation fault on Nginx 1.19.2 when i try to configure cache path zone.
