[patch 06/20] sysfs: sysfs_remove_dir() needs to invalidate the dentry

[Greg KH <gregkh@suse.de>]

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-stable review patch.  If anyone has any objections, please let us know.

------------------
When calling sysfs_remove_dir() don't allow any further sysfs functions
to work for this kobject anymore.  This fixes a nasty USB cdc-acm oops
on disconnect.

Many thanks to Bob Copeland and Paul Fulghum for taking the time to
track this down.

Cc: Bob Copeland <email@bobcopeland.com>
Cc: Paul Fulghum <paulkf@microgate.com>
Cc: Maneesh Soni <maneesh@in.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---

 fs/sysfs/dir.c   |    1 +
 fs/sysfs/inode.c |    6 +++++-
 2 files changed, 6 insertions(+), 1 deletion(-)

641e6f30a095f3752ed84fd9d279382f5d3ef4c1
--- linux-2.6.16.orig/fs/sysfs/dir.c
+++ linux-2.6.16/fs/sysfs/dir.c
@@ -302,6 +302,7 @@ void sysfs_remove_dir(struct kobject * k
 	 * Drop reference from dget() on entrance.
 	 */
 	dput(dentry);
+	kobj->dentry = NULL;
 }
 
 int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
--- linux-2.6.16.orig/fs/sysfs/inode.c
+++ linux-2.6.16/fs/sysfs/inode.c
@@ -227,12 +227,16 @@ void sysfs_drop_dentry(struct sysfs_dire
 void sysfs_hash_and_remove(struct dentry * dir, const char * name)
 {
 	struct sysfs_dirent * sd;
-	struct sysfs_dirent * parent_sd = dir->d_fsdata;
+	struct sysfs_dirent * parent_sd;
+
+	if (!dir)
+		return;
 
 	if (dir->d_inode == NULL)
 		/* no inode means this hasn't been made visible yet */
 		return;
 
+	parent_sd = dir->d_fsdata;
 	mutex_lock(&dir->d_inode->i_mutex);
 	list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
 		if (!sd->s_element)

--