From owner-freebsd-geom@FreeBSD.ORG  Sun Feb  1 10:26:26 2004
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To: Lukas Ertl <l.ertl@univie.ac.at>
From: "Poul-Henning Kamp" <phk@phk.freebsd.dk>
In-Reply-To: Your message of "Sun, 01 Feb 2004 19:12:57 +0100."
             <20040201190653.M613@korben.in.tern> 
Date: Sun, 01 Feb 2004 19:26:21 +0100
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cc: sos@freebsd.org
cc: freebsd-geom@freebsd.org
Subject: Re: Panic in g_disk_done() with atacontrol detach 
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In message <20040201190653.M613@korben.in.tern>, Lukas Ertl writes:
>Hi,
>
>I can provoke a panic when doing "atacontrol detach 1" if there's an
>active filesystem on the disk being detached.  The panic happens in
>g_disk_done() at:
>
>     devstat_end_transaction_bio(dp->d_devstat, bp2);
>
>The problem obviously is that ad_detach() calls disk_destroy() which nulls
>out the softc, and in g_disk_done() this softc is referenced again.
>
>The question is: is this an unsupported operation in the sense of "don't
>do that"?  If yes, then "atacontrol detach" should probably refuse to do
>the actual detach when there are I/O requests running, this would prevent
>a lot of foot shooting.

No, this should work.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.