Panic in g_disk_done() with atacontrol detach

[Poul-Henning Kamp]

In message <20040201190653.M613 at 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
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Never attribute to malice what can adequately be explained by incompetence.