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Neil Bothwick <neil@××××××××××.uk> wrote: |
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> On Thu, 27 Apr 2017 16:56:00 -0500, Dale wrote: |
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> |
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> > One thing about alt sysreq, once you get to a certain point, you |
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> > have to go "all the way" with it. I've found that just the R and E |
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> > generally gets things back to a point it is accessible and I don't |
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> > have to go through it all. I think once you get to the I or S, |
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> > it's all or nothing at that point. Even after the E, you may have |
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> > to start/restart some init processes. FYI, I'm pretty sure the S |
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> > is what syncs the file systems and the U unmounts everything. Of |
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> > course, the B reboots. I can't recall what the others do exactly. |
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> |
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> R resets the keyboard. E sends a SIGTERM to all processes except PID1, |
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> which is why you need to restart services after pressing it. I sends a |
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> SIGKILL similarly. As you say S syncs ass filesystems, U unmounts |
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> filesystems and remounts them readonly and B reboots. |
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> |
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> Once you have got to E, you need to restart stuff. You may get away |
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> with switching runlevels to bring up all your services, or you may |
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> decide that once the system has got itself into a state that has you |
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> reaching for SysRq, a reboot is in order. |
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Most of the keys are documented here: |
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https://wiki.ubuntuusers.de/Magic_SysRQ/ |
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And even more in the kernel directory at Documentation/sysrq.txt. |
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I will pin these synopsis onto the backside of my monitor. :-) |
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-- |
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Regards |
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wabe |
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