Date: Mon, 27 Feb 2012 12:31:33 -0700 From: Warner Losh <imp@bsdimp.com> To: John Baldwin <jhb@freebsd.org> Cc: Warner Losh <imp@freebsd.org>, new-bus@freebsd.org, des@freebsd.org Subject: Re: device_detach() never clears devclasses Message-ID: <DCABE43A-BA2D-4A6A-9743-A87827FF8013@bsdimp.com> In-Reply-To: <201202271208.15664.jhb@freebsd.org> References: <201202271208.15664.jhb@freebsd.org>
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This looks good to me. I think I should have had != here anyway. :)
Warner
On Feb 27, 2012, at 10:08 AM, John Baldwin wrote:
> I haven't reproduced this, I just have a hunch based on code-reading while
> fixing another bug. Ah, looking in SVN history it looks like this was broken
> in 129711 when device_attach() was split out of device_probe_and_attach().
> Specifically, if DEVICE_ATTACH() fails then this:
>
> /* Unset the class; set in device_probe_child */
> if (dev->devclass == NULL)
> (void)device_set_devclass(dev, NULL);
>
> is wrong. dev->devclass is always non-NULL at this point. However, we should
> be clearing the devclass for any device that doesn't have a fixed device
> class. And in fact that is what device_detach() does:
>
> if (!(dev->flags & DF_FIXEDCLASS))
> devclass_delete_device(dev->devclass, dev);
>
> The patch below fixes this:
>
> Index: subr_bus.c
> ===================================================================
> --- subr_bus.c (revision 232218)
> +++ subr_bus.c (working copy)
> @@ -2732,9 +2732,8 @@ device_attach(device_t dev)
> if ((error = DEVICE_ATTACH(dev)) != 0) {
> printf("device_attach: %s%d attach returned %d\n",
> dev->driver->name, dev->unit, error);
> - /* Unset the class; set in device_probe_child */
> - if (dev->devclass == NULL)
> - (void)device_set_devclass(dev, NULL);
> + if (!(dev->flags & DF_FIXEDCLASS))
> + devclass_delete_device(dev->devclass, dev);
> (void)device_set_driver(dev, NULL);
> device_sysctl_fini(dev);
> dev->state = DS_NOTPRESENT;
>
>
> --
> John Baldwin
>
>
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