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To: Andriy Gapon <avg@FreeBSD.org>
cc: freebsd-geom@FreeBSD.org
Subject: Re: g_disk_done() vs a destroyed disk
In-reply-to: <cba9c9bf-97ad-e3ae-e209-ea91e49b5822@FreeBSD.org>
From: "Poul-Henning Kamp" <phk@phk.freebsd.dk>
References: <cba9c9bf-97ad-e3ae-e209-ea91e49b5822@FreeBSD.org>
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Date: Fri, 27 Jan 2017 21:55:04 +0000
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--------
In message <cba9c9bf-97ad-e3ae-e209-ea91e49b5822@FreeBSD.org>, Andriy Gapo=
n writes:
>
>I've seen a situation where g_disk_done() was called on a bio after the
>corresponding disk had been already destroyed via g_disk_destroy().
>That call resulted in a crash here:
>	devstat_end_transaction_bio_bt(sc->dp->d_devstat, bp, &now);
>because sc->dp was NULL.
>
>Is it a bug that we do not check for dp being NULL (or dp->d_destroyed be=
ing
>set) in g_disk_done() ?
>Or is it a bug that a controller driver called biodone() for that bio hav=
ing
>earlier called disk_destroy() ?

It is a driver bug to call disk_destroy() before purging all in-flight bio=
s
with biodone()

-- =

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=
.