I have just reproduced the problem with a fresh install with latest updates, and kept a detailed log as I did so. Perhaps someone can spot something I am doing wrong? I would assume that I'm doing something wrong, except comparable things work on Debian and with upstream, and my users also experienced the problem independently before I did. A fresh pair of eyes on this would be appreciated!
* Download Ubuntu Server 8.04.2 for i386, and burn it to a CD-R. I used the following, as fetched on 2009-07-01: http://ftp-mirror.internap.com/pub/ubuntu-releases/hardy/ubuntu-8.04.2-server-i386.iso * Use machine IBM/Lenovo ThinkPad T60 with Intel Core Duo (32-bit X86). (Note that we have also observed the same behavior on 64-bit server hardware.) * Plug machine into Ethernet. * Boot the CD-R and do the following: * Language: English * From CD boot menu, select: Check CD for defects. Result: "The CD-ROM integrity test was successful. The CD-ROM is valid." Reboot system. * Language: English * From CD boot menu, select: Test memory. Reboot after a lot of successful testing passing. * Language: English * From CD boot menu, select: Install Ubuntu Server. * Choose language: English * Country: United States * Detect keyboard layout: No. * Keyboard origin: USA * Keyboard layout: USA * Wait for some device scanning and installing and DHCP. * Hostname: myserver * Time zone: Eastern * Partition disks: Guided - use entire disk. Write changes to disk. * Wait for partitioning and fs creation. * Full name of new user: John Smith * Username: john * Supply password. * No HTTP proxy. * Additional software selection: OpenSSH server * Wait, then remove CD when ejected, then let reboot. * SSH into "myserver" as "john" from another machine. Subsequent commands are in this shell unless otherwise specified. * sudo su - * apt-get update * apt-get upgrade * Note that the following packages are upgraded (at approx. 10pm EDT 2009-07-10): apparmor apparmor-utils apt apt-utils base-files cpp-4.2 cron dash file gcc-4.2-base initscripts installation-report libcurl3-gnutls libgcc1 libgnutls13 libkrb53 libldap-2.4-2 libmagic1 libsasl2-2 libsasl2-modules libssl0.9.8 libstdc++6 libvolume-id0 linux-image-2.6.24-23-server linux-ubuntu-modules-2.6.24-23-server lsb-base lsb-release ntpdate python-apt sudo sysv-rc sysvutils tasksel tasksel-data tzdata udev update-manager-core * shutdown -r now * Wait for reboot. * SSH into "myserver" as "john" from another machine. Subsequent commands are in this shell unless otherwise specified. * sudo su - * apt-get install apache2 * Create file "/usr/lib/cgi-bin/forever" with the contents: ---- CUT HERE ---- #!/bin/sh echo "Content-Type: text/html" echo "" echo "BEFORE" while true ; do expr 1 + 1 > /dev/null done echo "AFTER" ---- CUT HERE ---- * chmod 0755 /usr/lib/cgi-bin/forever * /etc/init.d/apache2 stop * Edit "/etc/apache2/sites-available/default" to add an erroneous directive to the top of the file: "XXX" * /etc/init.d/apache2 start * Verify that the start failed because of the erroneous directive, which confirms this config file really is being used. * Edit "/etc/apache2/sites-available/default" to remove the erroneous "XXX" directive. Below the "ServerAdmin" directive line, add the directive: RLimitCPU 2 2 * /etc/init.d/apache2 start * From a Web browser, access "forever" CGI (using the appropriate address): http://192.168.1.79/cgi-bin/forever * Observe that "BEFORE" appears, and the HTTP connection remains open and loading. * Determine PID of the "forever" process (in this case 5179). ps auxwf | grep forever * cat /proc/5179/limits ---- CUT HERE ---- cat /proc/5179/limits Limit Soft Limit Hard Limit Units Max cpu time unlimited unlimited ms Max file size unlimited unlimited bytes Max data size unlimited unlimited bytes Max stack size 8388608 unlimited bytes Max core file size 0 unlimited bytes Max resident set unlimited unlimited bytes Max processes 24566 24566 processes Max open files 1024 1024 files Max locked memory 32768 32768 bytes Max address space unlimited unlimited bytes Max file locks unlimited unlimited locks Max pending signals 24566 24566 signals Max msgqueue size 819200 819200 bytes Max nice priority 0 0 Max realtime priority 0 0 ---- CUT HERE ---- * Observe that CPU time is "unlimited". * dpkg -l | grep apache ---- CUT HERE ---- ii apache2 2.2.8-1ubuntu0.9 Next generation, scalable, extendable web se ii apache2-mpm-worker 2.2.8-1ubuntu0.9 High speed threaded model for Apache HTTPD ii apache2-utils 2.2.8-1ubuntu0.9 utility programs for webservers ii apache2.2-common 2.2.8-1ubuntu0.9 Next generation, scalable, extendable web se ---- CUT HERE ---- * Observe that "forever" process is still running even after 20 CPU seconds (and several wall clock minutes) have accrued. * Observe that HTTP connection and loading is browser is still happening. * dpkg -l | grep linux-image ---- CUT HERE ---- ii linux-image-2.6.24-23-server 2.6.24-23.52 Linux kernel image for version 2.6.24 on x86 ii linux-image-server 2.6.24.23.25 Linux kernel image on Server Equipment. ---- CUT HERE ---- * cat /proc/5179/status ---- CUT HERE ---- Name: forever State: R (running) Tgid: 5179 Pid: 5179 PPid: 5120 TracerPid: 0 Uid: 33 33 33 33 Gid: 33 33 33 33 FDSize: 32 Groups: 33 VmPeak: 1772 kB VmSize: 1772 kB VmLck: 0 kB VmHWM: 500 kB VmRSS: 500 kB VmData: 168 kB VmStk: 84 kB VmExe: 76 kB VmLib: 1420 kB VmPTE: 12 kB Threads: 1 SigQ: 0/24566 SigPnd: 0000000000000000 ShdPnd: 0000000000000000 SigBlk: 0000000000000000 SigIgn: 0000000000000000 SigCgt: 0000000000000002 CapInh: 0000000000000000 CapPrm: 0000000000000000 CapEff: 0000000000000000 Cpus_allowed: 03 Mems_allowed: 1 voluntary_ctxt_switches: 852381 nonvoluntary_ctxt_switches: 1233444 ---- CUT HERE ---- * ps auxwf The following is a subset of the output. ---- CUT HERE ---- root 5119 0.0 0.0 10472 2596 ? Ss 22:47 0:00 /usr/sbin/apache2 -k start www-data 5120 0.0 0.0 10244 1848 ? S 22:47 0:00 \_ /usr/sbin/apache2 -k start www-data 5179 6.3 0.0 1772 500 ? R 22:48 0:55 | \_ /bin/sh /usr/lib/cgi-bin/forever www-data 23160 0.0 0.0 0 0 ? Z 23:03 0:00 | \_ [expr] <defunct> www-data 5122 0.0 0.0 231808 2400 ? Sl 22:47 0:00 \_ /usr/sbin/apache2 -k start www-data 5126 0.0 0.0 231808 2840 ? Sl 22:47 0:00 \_ /usr/sbin/apache2 -k start ---- CUT HERE ---- * Try rebooting, to see if "forever" is correctly terminated by Apache if Apache is started at boot time, rather than from within the "sudo su -": shutdown -r now * Wait for reboot. * After comes back up, SSH in again as "john". Following commands are in SSH unless otherwise specified. * sudo su - * Request "forever" CGI in Web browser again: http://192.168.1.79/cgi-bin/forever * Observe that "forever" is not terminated by the "RLimitCPU", that the max cpu time in "/proc/<pid>/limits" is "unlimited", and that "strace" of the "forever" process continues running and showing heavy activity of creating its child processes. * Temporarily edit "forever" script to change the "expr" command to simply setting a variable so that no subprocesses are created, verify that nevertheless this version of the CGI also is not terminated by the "RLimitCPU". -- RLimitCPU has no effect in Apache https://bugs.launchpad.net/bugs/394350 You received this bug notification because you are a member of Ubuntu Bugs, which is a direct subscriber. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
