Re: 2.6.21-rc4-mm1

[Cornelia Huck <cornelia.huck@de.ibm.com>]

On Thu, 22 Mar 2007 07:23:06 -0500,
Larry Finger <larry.finger@lwfinger.net> wrote:

> Cornelia Huck wrote:
> > On Wed, 21 Mar 2007 23:39:17 -0800,
> > Andrew Morton <akpm@linux-foundation.org> wrote:
> > 
> >> On Wed, 21 Mar 2007 15:22:25 -0500 Matt Mackall <mpm@selenic.com> wrote:
> >>
> >>> With the latest -mm, I'm now getting this:
> >>>
> >>> Mar 21 15:06:52 cinder kernel: ipw2200: Detected Intel PRO/Wireless
> >>> 2200BG Network Connection
> >>> Mar 21 15:06:52 cinder kernel: firmware_loading_store: unexpected
> >>> value (0)
> >>> Mar 21 15:06:52 cinder kernel: ipw2200: ipw2200-bss.fw
> >>> request_firmware failed:
> >>> Reason -2
> >>> Mar 21 15:06:52 cinder kernel: ipw2200: Unable to load firmware: -2
> >>> Mar 21 15:06:52 cinder kernel: ipw2200: failed to register network
> >>> device
> >> The firmware loading bug is caused by
> >> driver-core-handles-kobject_uevent-failure-while-device_add.patch
> > 
> > Hm, this patch looks sane. It might be a good idea to enable
> > CONFIG_DEBUG_KOBJECT and find out why kobject_uevent() actually fails
> > in this case...
> 
> Attached is the appropriate portion of /var/log/messages with Kobject debugging enabled.

> Mar 22 07:01:42 larrylap2 kernel: kobject 0000:01:00.0: registering. parent: firmware, set: devices
> Mar 22 07:01:42 larrylap2 kernel: kobject_uevent_env
> Mar 22 07:01:42 larrylap2 kernel: fill_kobj_path: path = '/class/firmware/0000:01:00.0'
> Mar 22 07:01:42 larrylap2 kernel: fill_kobj_path: path = '/devices/pci0000:00/0000:00:02.0/0000:01:00.0'
> Mar 22 07:01:42 larrylap2 kernel: kobject_uevent_env
> Mar 22 07:01:42 larrylap2 ntpd[3434]: frequency initialized -31.513 PPM from /var/lib/ntp/drift/ntp.drift
> Mar 22 07:01:43 larrylap2 kernel: fill_kobj_path: path = '/class/firmware/0000:01:00.0'
> Mar 22 07:01:43 larrylap2 kernel: fill_kobj_path: path = '/devices/pci0000:00/0000:00:02.0/0000:01:00.0'
> Mar 22 07:01:43 larrylap2 kernel: firmware_loading_store: unexpected value (0)
> Mar 22 07:01:43 larrylap2 kernel: kobject_uevent_env
> Mar 22 07:01:43 larrylap2 kernel: fill_kobj_path: path = '/class/firmware/0000:01:00.0'
> Mar 22 07:01:43 larrylap2 kernel: fill_kobj_path: path = '/devices/pci0000:00/0000:00:02.0/0000:01:00.0'
> Mar 22 07:01:43 larrylap2 kernel: kobject 0000:01:00.0: cleaning up

(Repeating several times)

This would indicate that dev_uevent had been called. But how could
kobject_uevent then return an error without moaning about an uevent()
error code? Maybe the following debug patch could shed some light on
this (all moaning is prefixed with kobject_uevent_env, so it should be
easy to spot)...

---
 lib/kobject_uevent.c |   18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

--- linux-2.6.orig/lib/kobject_uevent.c
+++ linux-2.6/lib/kobject_uevent.c
@@ -85,11 +85,11 @@ int kobject_uevent_env(struct kobject *k
 	int retval = 0;
 	int j;
 
-	pr_debug("%s\n", __FUNCTION__);
+	pr_debug("%s: %s\n", __FUNCTION__, kobject_name(kobj));
 
 	action_string = action_to_string(action);
 	if (!action_string) {
-		pr_debug("kobject attempted to send uevent without action_string!\n");
+		pr_debug("%s: kobject attempted to send uevent without action_string!\n", __FUNCTION__);
 		return -EINVAL;
 	}
 
@@ -101,7 +101,7 @@ int kobject_uevent_env(struct kobject *k
 		} while (!top_kobj->kset && top_kobj->parent);
 	}
 	if (!top_kobj->kset) {
-		pr_debug("kobject attempted to send uevent without kset!\n");
+		pr_debug("%s: kobject attempted to send uevent without kset!\n", __FUNCTION__);
 		return -EINVAL;
 	}
 
@@ -111,7 +111,7 @@ int kobject_uevent_env(struct kobject *k
 	/*  skip the event, if the filter returns zero. */
 	if (uevent_ops && uevent_ops->filter)
 		if (!uevent_ops->filter(kset, kobj)) {
-			pr_debug("kobject filter function caused the event to drop!\n");
+			pr_debug("%s: kobject filter function caused the event to drop!\n", __FUNCTION__);
 			return 0;
 		}
 
@@ -121,18 +121,20 @@ int kobject_uevent_env(struct kobject *k
 	else
 		subsystem = kobject_name(&kset->kobj);
 	if (!subsystem) {
-		pr_debug("unset subsytem caused the event to drop!\n");
+		pr_debug("%s: unset subsytem caused the event to drop!\n", __FUNCTION__);
 		return 0;
 	}
 
 	/* environment index */
 	envp = kzalloc(NUM_ENVP * sizeof (char *), GFP_KERNEL);
-	if (!envp)
+	if (!envp) {
+		pr_debug("%s: couldn't alloc envp\n", __FUNCTION__);
 		return -ENOMEM;
-
+	}
 	/* environment values */
 	buffer = kmalloc(BUFFER_SIZE, GFP_KERNEL);
 	if (!buffer) {
+		pr_debug("%s: couldn't alloc buffer\n", __FUNCTION__);
 		retval = -ENOMEM;
 		goto exit;
 	}
@@ -140,6 +142,7 @@ int kobject_uevent_env(struct kobject *k
 	/* complete object path */
 	devpath = kobject_get_path(kobj, GFP_KERNEL);
 	if (!devpath) {
+		pr_debug("%s: couldn't get kobject path\n", __FUNCTION__);
 		retval = -ENOENT;
 		goto exit;
 	}
@@ -221,6 +224,7 @@ exit:
 	kfree(devpath);
 	kfree(buffer);
 	kfree(envp);
+	pr_debug("%s: returning %d\n", __FUNCTION__, retval);
 	return retval;
 }