Hi Ranier Caravan, Looks like this problem didn't go away.
To get symbols I had to first: sudo debuginfo-install httpd Then sudo gdb -p PID Several hundred apache forks are present so I selected random one.... *(gdb) where* #0 0x00007f247f302f0d in poll () at ../sysdeps/unix/syscall-template.S:81 #1 0x00007f247fa1e94b in poll (__timeout=30000, __nfds=1, __fds=0x7ffd5cd92b00) at /usr/include/bits/poll2.h:46 #2 apr_wait_for_io_or_timeout (f=f@entry=0x0, s=s@entry=0x55a9964b7610, for_read=for_read@entry=1) at support/unix/waitio.c:51 #3 0x00007f247fa1877a in apr_socket_recv (sock=sock@entry=0x55a9964b7610, buf=buf@entry=0x55a996541b08 "2\r\nh\n\r\n2\r\nh\n\r\n2\r\nh\n\r\n2\r\nh\n\r\ny: Express\r\nCache-Control: no-store, no-cache, no-transform, must-revalidate, max-age=0\r\nAccess-Control-Allow-Origin: *\r\nVary: Origin\r\nContent-Type: application/javascript;"..., len=len@entry=0x7ffd5cd92be0) at network_io/unix/sendrecv.c:87 #4 0x00007f2480457281 in socket_bucket_read (a=0x55a99653dc48, str=0x7ffd5cd92bd8, len=0x7ffd5cd92be0, block=<optimized out>) at buckets/apr_buckets_socket.c:36 #5 0x00007f2480455756 in apr_brigade_split_line (bbOut=bbOut@entry=0x55a9964d8ed8, bbIn=0x55a9964b7f28, block=block@entry=APR_BLOCK_READ, maxbytes=maxbytes@entry=8192) at buckets/apr_brigade.c:319 #6 0x000055a993422d5c in ap_core_input_filter (f=0x55a9964b7e28, b=0x55a9964d8ed8, mode=AP_MODE_GETLINE, block=APR_BLOCK_READ, readbytes=0) at core_filters.c:147 #7 0x00007f247a134c4e in logio_in_filter (f=<optimized out>, bb=0x55a9964d8ed8, mode=<optimized out>, block=<optimized out>, readbytes=<optimized out>) at mod_logio.c:140 #8 0x000055a99343e2bd in ap_http_filter (f=<optimized out>, b=<optimized out>, mode=<optimized out>, block=<optimized out>, readbytes=8192) at http_filters.c:515 #9 0x00007f2474eed058 in ap_proxy_http_process_response (p=p@entry=0x55a9965018e8, r=r@entry=0x55a996501960, backend_ptr=backend_ptr@entry=0x7ffd5cd97058, server_portstr=server_portstr@entry=0x7ffd5cd97100 "", conf=0x55a994beaef0, conf=0x55a994beaef0, worker=<optimized out>) at mod_proxy_http.c:1708 *#10 0x00007f2474eef7f9 in proxy_http_handler (r=<optimized out>, worker=<optimized out>, conf=0x55a994beaef0, url=0x55a9964d819e "http://nike.pbtech:3838/aln2tree/__sockjs__/n=zlsc268kyOEGKXGAXe/863/48gpkzl4/xhr_streaming <http://nike.pbtech:3838/aln2tree/__sockjs__/n=zlsc268kyOEGKXGAXe/863/48gpkzl4/xhr_streaming>", * * proxyname=0x0, proxyport=0) at mod_proxy_http.c:2038* *#11 0x00007f247673edc4 in proxy_run_scheme_handler (r=r@entry=0x55a996501960, worker=0x55a994beb1b0, conf=conf@entry=0x55a994beaef0, * * url=0x55a9964d819e "http://nike.pbtech:3838/aln2tree/__sockjs__/n=zlsc268kyOEGKXGAXe/863/48gpkzl4/xhr_streaming <http://nike.pbtech:3838/aln2tree/__sockjs__/n=zlsc268kyOEGKXGAXe/863/48gpkzl4/xhr_streaming>", proxyhost=proxyhost@entry=0x0, proxyport=proxyport@entry=0) at mod_proxy.c:2746* #12 0x00007f247673fcad in proxy_handler (r=0x55a996501960) at mod_proxy.c:1125 #13 0x000055a993427990 in ap_run_handler (r=r@entry=0x55a996501960) at config.c:169 #14 0x000055a993427ed9 in ap_invoke_handler (r=r@entry=0x55a996501960) at config.c:439 #15 0x000055a99343ca8a in ap_process_async_request (r=r@entry=0x55a996501960) at http_request.c:328 #16 0x000055a99343cd64 in ap_process_request (r=r@entry=0x55a996501960) at http_request.c:363 #17 0x000055a993438f62 in ap_process_http_sync_connection (c=0x55a9964a9090) at http_core.c:190 #18 ap_process_http_connection (c=0x55a9964a9090) at http_core.c:231 #19 0x000055a993430fc0 in ap_run_process_connection (c=c@entry=0x55a9964a9090) at connection.c:41 #20 0x000055a9934313a8 in ap_process_connection (c=c@entry=0x55a9964a9090, csd=<optimized out>) at connection.c:202 #21 0x00007f24769547af in child_main (child_num_arg=child_num_arg@entry=6) at prefork.c:707 #22 0x00007f24769549f5 in make_child (s=0x55a994af9e30, slot=6) at prefork.c:810 #23 0x00007f247695568e in perform_idle_server_maintenance (p=<optimized out>) at prefork.c:912 #24 prefork_run (_pconf=<optimized out>, plog=<optimized out>, s=<optimized out>) at prefork.c:1100 #25 0x000055a99340bffe in ap_run_mpm (pconf=pconf@entry=0x55a994ab5138, plog=0x55a994ae2358, s=0x55a994af9e30) at mpm_common.c:96 #26 0x000055a993404d76 in main (argc=2, argv=0x7ffd5cd97878) at main.c:783 *bt full for 10 and 11:* #10 0x00007f2474eef7f9 in proxy_http_handler (r=<optimized out>, worker=<optimized out>, conf=0x55a994beaef0, url=0x55a9964d819e " http://nike.pbtech:3838/aln2tree/__sockjs__/n=zlsc268kyOEGKXGAXe/863/48gpkzl4/xhr_streaming ", proxyname=0x0, proxyport=0) at mod_proxy_http.c:2038 locurl = 0x55a9964d8490 "/aln2tree/__sockjs__/n=zlsc268kyOEGKXGAXe/863/48gpkzl4/xhr_streaming" status = <optimized out> server_portstr = "\000vM\226\251U\000\000\350\030P\226\251U\000\000\000q\331\\\375\177\000\000\000\000\000\000\000\000\000" scheme = <optimized out> proxy_function = 0x7f2474ef0bfa "HTTP" u = <optimized out> backend = 0x55a9964b5600 is_ssl = 0 c = 0x55a9964a9090 retry = 0 p = <optimized out> uri = 0x55a9964d83b0 #11 0x00007f247673edc4 in proxy_run_scheme_handler (r=r@entry=0x55a996501960, worker=0x55a994beb1b0, conf=conf@entry=0x55a994beaef0, url=0x55a9964d819e " http://nike.pbtech:3838/aln2tree/__sockjs__/n=zlsc268kyOEGKXGAXe/863/48gpkzl4/xhr_streaming", proxyhost=proxyhost@entry=0x0, proxyport=proxyport@entry=0) at mod_proxy.c:2746 pHook = <optimized out> n = 3 rv = -1 I am beyond my knowledge limit at this point. The server nike.pbtech contains an R application running on internal server. It's reached through this Apace proxy. I have a few questions. 1) How do we tell the apache fork's hung hung? 2) How can I check all forks at once? Attaching to parent does not work. 3) When trying other Apache forks I get hung gdb at line "attaching to process." Any way to avoid? Thanks, Douglas Duckworth, MSc, LFCS HPC System Administrator Scientific Computing Unit Physiology and Biophysics Weill Cornell Medicine E: d...@med.cornell.edu O: 212-746-6305 F: 212-746-8690 On Mon, Nov 13, 2017 at 7:04 AM, Rainer Canavan <rainer.cana...@sevenval.com > wrote: > On Fri, Nov 10, 2017 at 6:41 PM, Douglas Duckworth > <dod2...@med.cornell.edu> wrote: > > Hi > > > > I am running old PHP under Apache httpd-2.4. > > [...] > > Though, ever few weeks, we see sudden increase in workers who never seem > to > > retire: > > > > [Fri Nov 10 02:43:20.019924 2017] [mpm_prefork:error] [pid 13584] > AH00161: > > server reached MaxRequestWorkers setting, consider raising the > > MaxRequestWorkers setting > > > > user@server[/var/www]$ ps aux | grep [h]ttpd | wc -l > > 257 > > If the php locks up while processing your request, no logs will be > written. You may be running > into a bug where circular, unresolvable dependencies for a lock > prevent the processes from > completing their requests. To check what's going on, install gdb, the > debug info for your php > and httpd and find the .gdbinfo that came with the httpd and php > version you're using. Then > attach gdb to any of the hanging processes (gdb `which httpd` PID), > source both .gdbinit files, > do a "zbacktrace" and a "bt full", and repeat for some other hanging > processes. Depending > on the type of lock, you may be able to identify the first process > that has acquired that lock > that all others are waiting for, and the php code and / or php module > that causes it. > > rainer > > --------------------------------------------------------------------- > To unsubscribe, e-mail: users-unsubscr...@httpd.apache.org > For additional commands, e-mail: users-h...@httpd.apache.org > >