Date: Mon, 27 Feb 2012 12:08:15 -0500 From: John Baldwin <jhb@freebsd.org> To: Warner Losh <imp@freebsd.org> Cc: new-bus@freebsd.org, des@freebsd.org Subject: device_detach() never clears devclasses Message-ID: <201202271208.15664.jhb@freebsd.org>
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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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