* signal to PID 1 from serial console like KeyboardRequest or CAD @ 2011-03-11 13:43 Jeremy Jackson 0 siblings, 0 replies; 8+ messages in thread From: Jeremy Jackson @ 2011-03-11 13:43 UTC (permalink / raw) To: linux-console Hi, I ran into a problem recently on a Linux server with a remote serial console. /sbin/init (actually Upstart) was in a state where nothing (useful) was running. I had to power cycle the machine to get back to the boot prompt. This has the side-effect of triggering raid rebuilds. It would be nice to have what Ctrl-Alt-Del does at the VGA console with PS/2 or USB keyboard. This sends a SIGINT to PID 1, and most distros have this set to do "shutdown -r now" which attempts a clean reboot. Once upon a time there was KeyboardRequest, which would send a SIGWINCH to PID 1 (when pressing Alt-UP_arrow?). I don't see any sign of this feature in Linux 2.6.32 though. Looking at the Sysrq handlers in the kernel I don't see any keystrokes that send SIGINT to PID 1 either. So, I'm wondering if it makes sense to add a Sysrq key to send a signal to PID1 ? -- Coplanar Networks http://www.coplanar.net (519)489-4903 ^ permalink raw reply [flat|nested] 8+ messages in thread
* signal to PID 1 from serial console like KeyboardRequest or CAD @ 2011-03-25 17:41 Jeremy Jackson 2011-03-31 19:57 ` Randy Dunlap 0 siblings, 1 reply; 8+ messages in thread From: Jeremy Jackson @ 2011-03-25 17:41 UTC (permalink / raw) To: linux-kernel Hi, Sent to linux-console with no reply for over a week... I ran into a problem recently on a Linux server with a remote serial console. /sbin/init (actually Upstart) was in a state where nothing (useful) was running. I had to power cycle the machine to get back to the boot prompt. This has the side-effect of triggering raid rebuilds. It would be nice to have what Ctrl-Alt-Del does at the VGA console with PS/2 or USB keyboard. This sends a SIGINT to PID 1, and most distros have this set to do "shutdown -r now" which attempts a clean reboot. Once upon a time there was KeyboardRequest, which would send a SIGWINCH to PID 1 (when pressing Alt-UP_arrow?). I don't see any sign of this feature in Linux 2.6.32 though. Looking at the Sysrq handlers in the kernel I don't see any keystrokes that send SIGINT to PID 1 either. So, I'm wondering if it makes sense to add a Sysrq key to send a signal to PID1 ? -- Coplanar Networks http://www.coplanar.net (519)489-4903 ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: signal to PID 1 from serial console like KeyboardRequest or CAD 2011-03-25 17:41 Jeremy Jackson @ 2011-03-31 19:57 ` Randy Dunlap 2011-04-01 5:37 ` Dmitry Torokhov 0 siblings, 1 reply; 8+ messages in thread From: Randy Dunlap @ 2011-03-31 19:57 UTC (permalink / raw) To: Jeremy Jackson; +Cc: linux-kernel, Dmitry Torokhov On Fri, 25 Mar 2011 13:41:40 -0400 Jeremy Jackson wrote: > Hi, > > Sent to linux-console with no reply for over a week... > > I ran into a problem recently on a Linux server with a remote serial > console. /sbin/init (actually Upstart) was in a state where nothing > (useful) was running. I had to power cycle the machine to get back to > the boot prompt. This has the side-effect of triggering raid rebuilds. > > It would be nice to have what Ctrl-Alt-Del does at the VGA console with > PS/2 or USB keyboard. This sends a SIGINT to PID 1, and most distros > have this set to do "shutdown -r now" which attempts a clean reboot. so C_A_D works at console via PS/2 or USB keyboard, but not on a remote serial console? Could it be an issue with whatever remote/serial software you are using? > Once upon a time there was KeyboardRequest, which would send a SIGWINCH > to PID 1 (when pressing Alt-UP_arrow?). I don't see any sign of this > feature in Linux 2.6.32 though. I couldn't find it in 2.4.37 either. Can 'loadkeys' help you any? > Looking at the Sysrq handlers in the kernel I don't see any keystrokes > that send SIGINT to PID 1 either. > > So, I'm wondering if it makes sense to add a Sysrq key to send a signal > to PID1 ? Dmitry, any ideas? --- ~Randy *** Remember to use Documentation/SubmitChecklist when testing your code *** ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: signal to PID 1 from serial console like KeyboardRequest or CAD 2011-03-31 19:57 ` Randy Dunlap @ 2011-04-01 5:37 ` Dmitry Torokhov 2011-04-01 15:39 ` Jeremy Jackson 0 siblings, 1 reply; 8+ messages in thread From: Dmitry Torokhov @ 2011-04-01 5:37 UTC (permalink / raw) To: Randy Dunlap; +Cc: Jeremy Jackson, linux-kernel On Thu, Mar 31, 2011 at 12:57:06PM -0700, Randy Dunlap wrote: > On Fri, 25 Mar 2011 13:41:40 -0400 Jeremy Jackson wrote: > > > Hi, > > > > Sent to linux-console with no reply for over a week... > > > > I ran into a problem recently on a Linux server with a remote serial > > console. /sbin/init (actually Upstart) was in a state where nothing > > (useful) was running. I had to power cycle the machine to get back to > > the boot prompt. This has the side-effect of triggering raid rebuilds. > > > > It would be nice to have what Ctrl-Alt-Del does at the VGA console with > > PS/2 or USB keyboard. This sends a SIGINT to PID 1, and most distros > > have this set to do "shutdown -r now" which attempts a clean reboot. > > so C_A_D works at console via PS/2 or USB keyboard, but not on a remote > serial console? Could it be an issue with whatever remote/serial software > you are using? I believe it is simply a matter of console keymap and assigning "boot" value to the desired combination. > > > Once upon a time there was KeyboardRequest, which would send a SIGWINCH > > to PID 1 (when pressing Alt-UP_arrow?). I don't see any sign of this > > feature in Linux 2.6.32 though. > > I couldn't find it in 2.4.37 either. > > Can 'loadkeys' help you any? > > > Looking at the Sysrq handlers in the kernel I don't see any keystrokes > > that send SIGINT to PID 1 either. > > > > So, I'm wondering if it makes sense to add a Sysrq key to send a signal > > to PID1 ? > > Dmitry, any ideas? We have SysRq bindings to unmount filesystems and reboot, isn't that enough? -- Dmitry ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: signal to PID 1 from serial console like KeyboardRequest or CAD 2011-04-01 5:37 ` Dmitry Torokhov @ 2011-04-01 15:39 ` Jeremy Jackson 2011-04-01 15:42 ` Randy Dunlap 0 siblings, 1 reply; 8+ messages in thread From: Jeremy Jackson @ 2011-04-01 15:39 UTC (permalink / raw) To: Dmitry Torokhov; +Cc: Randy Dunlap, linux-kernel On 04/01/2011 01:37 AM, Dmitry Torokhov wrote: > On Thu, Mar 31, 2011 at 12:57:06PM -0700, Randy Dunlap wrote: >> On Fri, 25 Mar 2011 13:41:40 -0400 Jeremy Jackson wrote: >> >>> Hi, >>> >>> Sent to linux-console with no reply for over a week... >>> >>> I ran into a problem recently on a Linux server with a remote serial >>> console. /sbin/init (actually Upstart) was in a state where nothing >>> (useful) was running. I had to power cycle the machine to get back to >>> the boot prompt. This has the side-effect of triggering raid rebuilds. >>> >>> It would be nice to have what Ctrl-Alt-Del does at the VGA console with >>> PS/2 or USB keyboard. This sends a SIGINT to PID 1, and most distros >>> have this set to do "shutdown -r now" which attempts a clean reboot. >> >> so C_A_D works at console via PS/2 or USB keyboard, but not on a remote >> serial console? Could it be an issue with whatever remote/serial software >> you are using? > > I believe it is simply a matter of console keymap and assigning "boot" > value to the desired combination. The VGA console/keyboard isn't an issue here, C_A_D works great. The problem is, that functionality isn't available when using *serial* console. >>> Once upon a time there was KeyboardRequest, which would send a SIGWINCH >>> to PID 1 (when pressing Alt-UP_arrow?). I don't see any sign of this >>> feature in Linux 2.6.32 though. >> >> I couldn't find it in 2.4.37 either. >> >> Can 'loadkeys' help you any? >> >>> Looking at the Sysrq handlers in the kernel I don't see any keystrokes >>> that send SIGINT to PID 1 either. >>> >>> So, I'm wondering if it makes sense to add a Sysrq key to send a signal >>> to PID1 ? >> >> Dmitry, any ideas? > > We have SysRq bindings to unmount filesystems and reboot, isn't that > enough? Reboot isn't clean... it doesn't signal MD-raid to "unmount" does it? SysRq powerOff does cleanly shutdown md-raid, but who will drive to the datacenter to press the power button to turn it back on? I guess there are two ways to achieve clean (md-raid) reboot when using serial console... a new SysRq to reboot "clean", or a new SysRq to signal init. Looking at ctrlaltdel(8), perhaps it could just one SysRq, and let userspace (/sbin/init) configure it as needed. -- Coplanar Networks http://www.coplanar.net (519)489-4903 ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: signal to PID 1 from serial console like KeyboardRequest or CAD 2011-04-01 15:39 ` Jeremy Jackson @ 2011-04-01 15:42 ` Randy Dunlap 2011-04-01 15:47 ` Jeremy Jackson 0 siblings, 1 reply; 8+ messages in thread From: Randy Dunlap @ 2011-04-01 15:42 UTC (permalink / raw) To: Jeremy Jackson; +Cc: Dmitry Torokhov, linux-kernel On Fri, 01 Apr 2011 11:39:28 -0400 Jeremy Jackson wrote: > On 04/01/2011 01:37 AM, Dmitry Torokhov wrote: > > On Thu, Mar 31, 2011 at 12:57:06PM -0700, Randy Dunlap wrote: > >> On Fri, 25 Mar 2011 13:41:40 -0400 Jeremy Jackson wrote: > >> > >>> Hi, > >>> > >>> Sent to linux-console with no reply for over a week... > >>> > >>> I ran into a problem recently on a Linux server with a remote serial > >>> console. /sbin/init (actually Upstart) was in a state where nothing > >>> (useful) was running. I had to power cycle the machine to get back to > >>> the boot prompt. This has the side-effect of triggering raid rebuilds. > >>> > >>> It would be nice to have what Ctrl-Alt-Del does at the VGA console with > >>> PS/2 or USB keyboard. This sends a SIGINT to PID 1, and most distros > >>> have this set to do "shutdown -r now" which attempts a clean reboot. > >> > >> so C_A_D works at console via PS/2 or USB keyboard, but not on a remote > >> serial console? Could it be an issue with whatever remote/serial software > >> you are using? > > > > I believe it is simply a matter of console keymap and assigning "boot" > > value to the desired combination. > > The VGA console/keyboard isn't an issue here, C_A_D works great. The > problem is, that functionality isn't available when using *serial* console. That's why I asked whether it could be an issue with the serial interface software. E.g., minicom handles/processes certain keystrokes, other apps do things differently, etc... > >>> Once upon a time there was KeyboardRequest, which would send a SIGWINCH > >>> to PID 1 (when pressing Alt-UP_arrow?). I don't see any sign of this > >>> feature in Linux 2.6.32 though. > >> > >> I couldn't find it in 2.4.37 either. > >> > >> Can 'loadkeys' help you any? > >> > >>> Looking at the Sysrq handlers in the kernel I don't see any keystrokes > >>> that send SIGINT to PID 1 either. > >>> > >>> So, I'm wondering if it makes sense to add a Sysrq key to send a signal > >>> to PID1 ? > >> > >> Dmitry, any ideas? > > > > We have SysRq bindings to unmount filesystems and reboot, isn't that > > enough? > > Reboot isn't clean... it doesn't signal MD-raid to "unmount" does it? > SysRq powerOff does cleanly shutdown md-raid, but who will drive to the > datacenter to press the power button to turn it back on? > > I guess there are two ways to achieve clean (md-raid) reboot when using > serial console... a new SysRq to reboot "clean", or a new SysRq to > signal init. Looking at ctrlaltdel(8), perhaps it could just one SysRq, > and let userspace (/sbin/init) configure it as needed. > > > -- > Coplanar Networks > http://www.coplanar.net > (519)489-4903 > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ --- ~Randy *** Remember to use Documentation/SubmitChecklist when testing your code *** ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: signal to PID 1 from serial console like KeyboardRequest or CAD 2011-04-01 15:42 ` Randy Dunlap @ 2011-04-01 15:47 ` Jeremy Jackson 2011-04-01 15:59 ` Dmitry Torokhov 0 siblings, 1 reply; 8+ messages in thread From: Jeremy Jackson @ 2011-04-01 15:47 UTC (permalink / raw) To: Randy Dunlap; +Cc: Dmitry Torokhov, linux-kernel On 04/01/2011 11:42 AM, Randy Dunlap wrote: > On Fri, 01 Apr 2011 11:39:28 -0400 Jeremy Jackson wrote: > >> On 04/01/2011 01:37 AM, Dmitry Torokhov wrote: >>> On Thu, Mar 31, 2011 at 12:57:06PM -0700, Randy Dunlap wrote: >>>> On Fri, 25 Mar 2011 13:41:40 -0400 Jeremy Jackson wrote: >>>> >>>>> Hi, >>>>> >>>>> Sent to linux-console with no reply for over a week... >>>>> >>>>> I ran into a problem recently on a Linux server with a remote serial >>>>> console. /sbin/init (actually Upstart) was in a state where nothing >>>>> (useful) was running. I had to power cycle the machine to get back to >>>>> the boot prompt. This has the side-effect of triggering raid rebuilds. >>>>> >>>>> It would be nice to have what Ctrl-Alt-Del does at the VGA console with >>>>> PS/2 or USB keyboard. This sends a SIGINT to PID 1, and most distros >>>>> have this set to do "shutdown -r now" which attempts a clean reboot. >>>> >>>> so C_A_D works at console via PS/2 or USB keyboard, but not on a remote >>>> serial console? Could it be an issue with whatever remote/serial software >>>> you are using? >>> >>> I believe it is simply a matter of console keymap and assigning "boot" >>> value to the desired combination. >> >> The VGA console/keyboard isn't an issue here, C_A_D works great. The >> problem is, that functionality isn't available when using *serial* console. > > That's why I asked whether it could be an issue with the serial interface > software. E.g., minicom handles/processes certain keystrokes, other apps do things > differently, etc... OK I guess I should clarify... when using Linux serial console, you can send BREAK <letter> to use SysRq functions. In minicom, META-F sends break. This works fine for all the existing functions linux offers, r = reboot immediate, i = kill all tasks, etc. But, there is no function available to reboot *clean*, or to signal PID 1 (/sbin/init) to do same. So, minicom is working/configured properly, Linux just doesn't offer a feature similar to C_A_D via serial. -- Coplanar Networks http://www.coplanar.net (519)489-4903 ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: signal to PID 1 from serial console like KeyboardRequest or CAD 2011-04-01 15:47 ` Jeremy Jackson @ 2011-04-01 15:59 ` Dmitry Torokhov 0 siblings, 0 replies; 8+ messages in thread From: Dmitry Torokhov @ 2011-04-01 15:59 UTC (permalink / raw) To: Jeremy Jackson; +Cc: Randy Dunlap, linux-kernel On Fri, Apr 01, 2011 at 11:47:10AM -0400, Jeremy Jackson wrote: > On 04/01/2011 11:42 AM, Randy Dunlap wrote: > >On Fri, 01 Apr 2011 11:39:28 -0400 Jeremy Jackson wrote: > > > >>On 04/01/2011 01:37 AM, Dmitry Torokhov wrote: > >>>On Thu, Mar 31, 2011 at 12:57:06PM -0700, Randy Dunlap wrote: > >>>>On Fri, 25 Mar 2011 13:41:40 -0400 Jeremy Jackson wrote: > >>>> > >>>>>Hi, > >>>>> > >>>>>Sent to linux-console with no reply for over a week... > >>>>> > >>>>>I ran into a problem recently on a Linux server with a remote serial > >>>>>console. /sbin/init (actually Upstart) was in a state where nothing > >>>>>(useful) was running. I had to power cycle the machine to get back to > >>>>>the boot prompt. This has the side-effect of triggering raid rebuilds. > >>>>> > >>>>>It would be nice to have what Ctrl-Alt-Del does at the VGA console with > >>>>>PS/2 or USB keyboard. This sends a SIGINT to PID 1, and most distros > >>>>>have this set to do "shutdown -r now" which attempts a clean reboot. > >>>> > >>>>so C_A_D works at console via PS/2 or USB keyboard, but not on a remote > >>>>serial console? Could it be an issue with whatever remote/serial software > >>>>you are using? > >>> > >>>I believe it is simply a matter of console keymap and assigning "boot" > >>>value to the desired combination. > >> > >>The VGA console/keyboard isn't an issue here, C_A_D works great. The > >>problem is, that functionality isn't available when using *serial* console. > > > >That's why I asked whether it could be an issue with the serial interface > >software. E.g., minicom handles/processes certain keystrokes, other apps do things > >differently, etc... > > OK I guess I should clarify... when using Linux serial console, you > can send BREAK <letter> to use SysRq functions. Ah, right, we hardwire BREAK to SysRq when using serial console... > In minicom, META-F > sends break. This works fine for all the existing functions linux > offers, r = reboot immediate, i = kill all tasks, etc. But, there > is no function available to reboot *clean*, or to signal PID 1 > (/sbin/init) to do same. So, minicom is working/configured > properly, Linux just doesn't offer a feature similar to C_A_D via > serial. SysRQ+REISUB should do it I think. -- Dmitry ^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2011-04-01 15:59 UTC | newest] Thread overview: 8+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2011-03-11 13:43 signal to PID 1 from serial console like KeyboardRequest or CAD Jeremy Jackson -- strict thread matches above, loose matches on Subject: below -- 2011-03-25 17:41 Jeremy Jackson 2011-03-31 19:57 ` Randy Dunlap 2011-04-01 5:37 ` Dmitry Torokhov 2011-04-01 15:39 ` Jeremy Jackson 2011-04-01 15:42 ` Randy Dunlap 2011-04-01 15:47 ` Jeremy Jackson 2011-04-01 15:59 ` Dmitry Torokhov
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