Re: kldunload DIAGNOSTIC idea...

From: Scott Long (scottl_at_samsco.org)
Date: 07/20/04

  • Next message: Scott Long: "Re: kldunload DIAGNOSTIC idea..." 
    Date: Tue, 20 Jul 2004 13:08:54 -0600
To: Brian Fundakowski Feldman <green@freebsd.org>

    Brian Fundakowski Feldman wrote:
    > On Tue, Jul 20, 2004 at 08:20:23PM +0200, Poul-Henning Kamp wrote:
    >
    >>I'm pulling hair out trying to make it guaranteed safe to unload device
    >>driver modules, and the major pain here is to make sure there is no
    >>thread stuck somewhere inside the code.
    >>
    >>That gave me the idea for a simple little DIAGNOSTIC check for kldunload:
    >>run through the proc/thread table and look for any thread with an
    >>instruction counter inside the range of pages we are going to unload.
    >>
    >>Any takers ?
    >
    >
    > You mean any thread with a stack trace that includes an instruction
    > counter inside those pages, don't you?
    >

    This is better than phk's suggestion since you can have module code
    that calls out to another part of the system and blocks. Still, it's
    not 100% perfect. There are all sorts of APIs out there that do async
    callbacks, and it really should be up to the driver to track these
    things.

    Scott
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  • Next message: Scott Long: "Re: kldunload DIAGNOSTIC idea..."

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    • Re: kldunload DIAGNOSTIC idea...
      ... > I'm pulling hair out trying to make it guaranteed safe to unload device ... > driver modules, and the major pain here is to make sure there is no ... > instruction counter inside the range of pages we are going to unload. ...
      (freebsd-arch)
    • Re: kldunload DIAGNOSTIC idea...
      ... >> I'm pulling hair out trying to make it guaranteed safe to unload device ... >> driver modules, and the major pain here is to make sure there is no ... >> instruction counter inside the range of pages we are going to unload. ... >You mean any thread with a stack trace that includes an instruction ...
      (freebsd-arch)
    • kldunload DIAGNOSTIC idea...
      ... I'm pulling hair out trying to make it guaranteed safe to unload device ... driver modules, and the major pain here is to make sure there is no ... thread stuck somewhere inside the code. ...
      (freebsd-arch)
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