Re: [PATCH] fix altsysrq deadlock

From: Jason Baron (jbaron_at_redhat.com)
Date: 10/26/04

  • Next message: John Richard Moser: "Re: PROPOSAL: New NEW development model"
    Date:	Tue, 26 Oct 2004 14:22:08 -0400 (EDT)
    To: John Richard Moser <nigelenki@comcast.net>
    
    

    On Tue, 26 Oct 2004, John Richard Moser wrote:

    > -----BEGIN PGP SIGNED MESSAGE-----
    > Hash: SHA1
    >
    >
    >
    > Jason Baron wrote:
    > | hi,
    > |
    >
    > HI! ^_^
    >
    > [...]
    >
    > | An
    > | altsyrq that produces no output might seem troublesome, but it is
    > | primarily used as a debugging tool, so trying it again seems reasonable.
    >
    > Actually, I use sysrq as if it's just another feature. It should (I
    > think it does. . . not sure) only work on the console directly, for
    > security reasons; but it's great when things like X misbehave, or when
    > I've damaged something and the system doesn't want to shut down. AS-E
    > AS-I AS-U AS-S AS-O. :) I actually tried making an N sysrq, for
    > "semi-Normal shutdown." It would send TERM, wait 5S, send KILL, wait
    > 5S, unmount, sync, reboot.
    >
    > Just thought it might be interesting to point out that magic-sysrq can
    > be a helpful feature for someone not hacking the kernel.
    >

    The patch only drops a sysrq that is about to cause a system deadlock. So
    if you haven't had any deadlocks this patch shouldn't have a noticeable
    affect.

    If a caller wants to rely on handle_sysrq, then it should not be called
    from interrupt context. handle_sysrq can not defer the work, since the
    point of sysrq is to be able get information out when the system is
    potentially unusable. How would you know when to defer the work and when
    not to?

    -Jason

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  • Next message: John Richard Moser: "Re: PROPOSAL: New NEW development model"

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