missing sysrq
I have compiled the magic sysrq as enabled in most kernels I've used for quite a while. Most recently 2.4.5-ac5, on a RH 7.1 SMP machine with APIC disabled. The /etc/sysctl.conf contains this line:
kernel.sysrq = 1
However, if I go to /proc/sys/kernel/sysrq does not exist. Nor is it possible for root to echo to that file name. Attempts to use the magic sysrq keys, such as for sync, prove that it truly is not enabled, or is otherwise missing. Has something changed in the enabling of magic sysrq? Or is this one of those strange "it should be there" things?
A second observation, maybe related (maybe not), is the /var/log/messages line:
sysctl: error: permission denied on key 'vm.freepages'
This particular line has occurred since install of RH 7.1, even with its original kernel, but continues into 2.4.5-ac5. The relevant line in /etc/sysctl.conf:
vm.freepages = 383 766 1149
This line is how the original RH 7.1 install set it up. This particular machine has 256 MB of ram, and somewhat over a 1 GB of swap. Is the vm.freepages not intended to be set in /etc/sysctl.conf? Or maybe the specs are off for this particular hardware? I know a lot of vm changes are going on in the kernel, and wondering if this could be something that used to be supported but no longer is.
D. Stimits, [email protected]
Quoted 1 line · In article <[email protected]> you wrote:
However, if I go to
/proc/sys/kernel/sysrqdoes not exist.
It is a compile time option, so the person who compiled your kernel left it out.
Quoted 1 line
vm.freepages = 383 766 1149
tat feature is removed in recent VM Systems.
Greetings
Bernd
Quoted 6 lines · Bernd Eckenfels
Quoted 1 line · In article <[email protected]> you wrote:
However, if I go to
/proc/sys/kernel/sysrqdoes not exist.It is a compile time option, so the person who compiled your kernel left it out.
I compiled it, and the sysrq is definitely in the config. No doubt at all. I also use make mrproper and config again before dep and actual compile. Maybe it is just a quirk/oddball.
D. Stimits, [email protected]
Quoted 12 lines
Quoted 2 lines
vm.freepages = 383 766 1149
tat feature is removed in recent VM Systems.
Greetings
Bernd
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Quoted 10 lines · D. Stimits
Date: Thu, 31 May 2001 17:48:34 -0600
From: D. Stimits <[email protected]>
To: unlisted-recipients:;;@timpanogas.com (no To-header on input)
Cc: [email protected]
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Subject: Re: missing sysrqQuoted 2 lines · Bernd Eckenfels
In article <[email protected]> you wrote:
Quoted 8 lines
Quoted 4 lines
Quoted 1 line
However, if I go to
/proc/sys/kernel/sysrqdoes not exist.It is a compile time option, so the person who compiled your kernel left it out.
I compiled it, and the sysrq is definitely in the config. No doubt at all. I also use make mrproper and config again before dep and actual compile. Maybe it is just a quirk/oddball.
What does this say:
ksyms -a |grep -i sysrq
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Mike A. Harris - Linux advocate - Open Source advocate
Opinions and viewpoints expressed are solely my own.
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Who knows what dangerous code lurks in the hearts of men? Only the Shadowman(TM) knows... Mike A. Harris <[email protected]>