Your message dated Wed, 21 Aug 2019 11:48:47 +0000 with message-id <[email protected]> and subject line closing on timeout: Please implement a kindler gentler single-user runlevel has caused the Debian Bug report #142424, regarding Please implement a kindler gentler single-user runlevel to be marked as done.
This means that you claim that the problem has been dealt with. If this is not the case it is now your responsibility to reopen the Bug report if necessary, and/or fix the problem forthwith. (NB: If you are a system administrator and have no idea what this message is talking about, this may indicate a serious mail system misconfiguration somewhere. Please contact [email protected] immediately.) -- 142424: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=142424 Debian Bug Tracking System Contact [email protected] with problems
--- Begin Message ---Package: sysvinit Version: 2.84-2 Severity: normal Going to single-user runlevel destroys ALL processes on the machine using signals, by calling "killall5" inside the init.d/S20single script, (probably because it does not trust individual /etc/init.d/XXX stop scripts ?) 1) I think this goes agains the original System V philosophy, 2) This makes the single-user mode "one-way only": it's *impossible* to go back to multi-user mode without rebooting, because vital daemons like DHCP or portmap were wrongly killed. 1) - extract from "man init" on woody: When init is requested to change the runlevel, it sends the warning signal SIGTERM to all processes that are undefined in the new runlevel. It then ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ waits 5 seconds before forcibly terminating these processes via the SIGKILL signal. Note that init assumes that all these processes (and their descen dants) remain in the same process group which init originally created for them. If any process changes its process group affiliation it will not receive these signals. Such processes need to be terminated separately. I find this quite different to killing "ALL" processes without restriction ! - extract from "man init" on Solaris 8: Run Level Changes When a run level change request is made, init sends the warning signal (SIGTERM) to all processes that are undefined ^^^^^^^^^^^^^^^^^ in the target run level. init waits five seconds before for- cibly terminating these processes by sending a kill signal (SIGKILL). Same read. Later: left mounted. During the transition down to single- user mode, all processes started by init or init.d scripts that should only be running in multi-user mode are killed. 2) Some vital services, like init.d/networking and init.d/portmap for instance, are meant to be launched at boot and never stopped. The problem is they rely on a active process to function properly. Going to single user mode stop these services wrongly, and even worse: brutaly (not even calling their /etc/init.d/XXX stop script). So a return to a working multi-user mode imply a lenghty reboot (and this can be learned the hard way !) 3) Suggested workarounds (some of them are cumulative, some other mutually exclusive): - modify the init man page to advertise the fact that returning from single-user mode kills really ALL processes. - ask daemons maintainers to take this single-user specificity into consideration - rerun boot scripts after entering single-user mode ? - implement a "softer single-user mode" (for instance runlevel number 2), which would just bring down services with /etc/init.d/XXX stop scripts, and no brutal signals. 4) This "cannot return from single-user mode" bug is related to the very old bug #16273 : <http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=16273> "cannot enter single user mode remotely" -- System Information Debian Release: 3.0 Architecture: i386 Kernel: Linux cartman 2.2.20 #2 Tue Dec 18 20:21:39 CET 2001 i686 Locale: LANG=fr, LC_CTYPE=fr_FR Versions of packages sysvinit depends on: ii dpkg 1.9.20 Package maintenance system for Deb ii e2fsprogs 1.27-2 The EXT2 file system utilities and ii libc6 2.2.5-4 GNU C Library: Shared libraries an ii mount 2.11n-4 Tools for mounting and manipulatin ii util-linux 2.11n-4 Miscellaneous system utilities.
--- End Message ---
--- Begin Message ---This bug was tagged 'moreinfo', which means that bug can't be addressed until more information is provided. Since no additional information was provided for 6 months, bug is hereby closed. If you believe this is mistake and required information is actually present, or if you want to provide extra information, please reopen bug and remove 'moreinfo' tag. Documentation about bug manipulation can be found at https://www.debian.org/Bugs/server-control.en.html -- This email is created semi-automatically; if it causes disruption or otherwise harms normal Debian workflow, please complain.
--- End Message ---
