Re: OOPS on module unload 2.5.47-mm1

[Patrick Mansfield <patmans@us.ibm.com>]

On Tue, Nov 12, 2002 at 03:49:40PM -0800, Badari Pulavarty wrote:
> Hi,
> 
> I get following panic while rmmod qla driver.  (2.5.47-mm1).
> 
> Is this a known problem ? Any ideas ?
> 
> Thanks,
> Badari

Badari -

Here are four patches, 3 in sysfs, one in scsi, that I used to enable
rmmod/insmod of qla and scsi_debug without problems in 2.5.46 or so.
I have not tried running 2.5.47-mm1 or 2.5.47 with these, but these
patches still apply against current bk (nov 13). I don't remember all
the odd behaviour seen without them, generally use-after-freed problems.

I'm not sure about the sysfs ones, but the scsi one is fine for now
(exporting the SCSI type is not very useful, we need a common scsi_device
removal/cleanup function where we can remove scsi_device sysfs attribute
files. Generally, scsi use of sysfs is broken.)

I posted these to linux-scsi, Mike A posted the sysfs ones to linux-kernel.

--- 1.22/drivers/base/bus.c	Thu Oct 31 08:20:23 2002
+++ edited/drivers/base/bus.c	Wed Nov  6 17:03:24 2002
@@ -209,8 +209,10 @@
 				attach(dev);
 			else
 				dev->driver = NULL;
-		} else 
+		} else  {
 			attach(dev);
+			error = 0;
+		}
 	}
 	return error;
 }
===== drivers/base/core.c 1.50 vs edited =====
--- 1.50/drivers/base/core.c	Thu Oct 31 08:20:23 2002
+++ edited/drivers/base/core.c	Wed Nov  6 17:03:42 2002
@@ -173,8 +173,6 @@
 		return -EINVAL;
 
 	device_initialize(dev);
-	if (dev->parent)
-		get_device(dev->parent);
 	error = device_add(dev);
 	if (error && dev->parent)
 		put_device(dev->parent);
===== drivers/base/driver.c 1.14 vs edited =====
--- 1.14/drivers/base/driver.c	Wed Oct 30 16:35:48 2002
+++ edited/drivers/base/driver.c	Wed Nov  6 16:44:13 2002
@@ -127,6 +127,8 @@
 	drv->present = 0;
 	spin_unlock(&device_lock);
 	pr_debug("driver %s:%s: unregistering\n",drv->bus->name,drv->name);
+	bus_remove_driver(drv);
+	kobject_unregister(&drv->kobj);
 	put_driver(drv);
 }
 
--- 1.33/drivers/scsi/scsi_scan.c	Wed Nov  6 11:46:48 2002
+++ edited/drivers/scsi/scsi_scan.c	Wed Nov  6 17:04:56 2002
@@ -307,73 +307,6 @@
 }
 
 /**
- * scsi_device_type_read - copy out the SCSI type
- * @driverfs_dev:	driverfs device to check
- * @page:		copy data into this area
- * @count:		number of bytes to copy
- * @off:		start at this offset in page
- *
- * Description:
- *     Called via driverfs when the "type" (in scsi_device_type_file)
- *     field is read. Copy the appropriate SCSI type string into @page,
- *     followed by a newline and a '\0'. Go through gyrations so we don't
- *     write more than @count, and we don't write past @off.
- *
- * Notes:
- *     This is for the top-most scsi entry in driverfs, the upper-level
- *     drivers have their own type file. XXX This is not part of scanning,
- *     other than we reference the attr struct in this file, move to
- *     scsi.c or scsi_lib.c.
- *
- * Return:
- *     number of bytes written into page.
- **/
-static ssize_t scsi_device_type_read(struct device *driverfs_dev, char *page,
-	size_t count, loff_t off)
-{
-	struct scsi_device *sdev = to_scsi_device(driverfs_dev);
-	const char *type;
-	size_t size, len;
-
-	if ((sdev->type > MAX_SCSI_DEVICE_CODE) ||
-	    (scsi_device_types[(int)sdev->type] == NULL))
-		type = "Unknown";
-	else
-		type = scsi_device_types[(int)sdev->type];
-	size = strlen(type);
-	/*
-	 * Check if off is past size + 1 for newline + 1 for a '\0'.
-	 */
-	if (off >= (size + 2))
-		return 0;
-	if (size > off) {
-		len = min((size_t) (size - off), count);
-		memcpy(page + off, type + off, len);
-	} else
-		len = 0;
-	if (((len + off) == size) && (len < count))
-		/*
-		 * We are at the end of the string and have space, add a
-		 * new line.
-		 */
-		*(page + off + len++) = '\n';
-	if (((len + off) == (size + 1)) && (len < count))
-		/*
-		 * We are past the newline and have space, add a
-		 * terminating '\0'.
-		 */
-		*(page + off + len++) = '\0';
-	return len;
-}
-
-/*
- * Create dev_attr_type. This is different from the dev_attr_type in scsi
- * upper level drivers.
- */
-static DEVICE_ATTR(type,S_IRUGO,scsi_device_type_read,NULL);
-
-
-/**
  * print_inquiry - printk the inquiry information
  * @inq_result:	printk this SCSI INQUIRY
  *
@@ -1439,11 +1372,6 @@
 	sdev->sdev_driverfs_dev.parent = &sdev->host->host_driverfs_dev;
 	sdev->sdev_driverfs_dev.bus = &scsi_driverfs_bus_type;
 	device_register(&sdev->sdev_driverfs_dev);
-
-	/*
-	 * Create driverfs file entries
-	 */
-	device_create_file(&sdev->sdev_driverfs_dev, &dev_attr_type);
 
 	sprintf(devname, "host%d/bus%d/target%d/lun%d",
 		sdev->host->host_no, sdev->channel, sdev->id, sdev->lun);