Commit cc57c073 authored by Mike Christie's avatar Mike Christie Committed by Christoph Hellwig
Browse files

configfs: fix registered group removal

This patch fixes a bug where configfs_register_group had added
a group in a tree, and userspace has done a rmdir on a dir somewhere
above that group and we hit a kernel crash. The problem is configfs_rmdir
will detach everything under it and unlink groups on the default_groups
list. It will not unlink groups added with configfs_register_group so when
configfs_unregister_group is called to drop its references to the group/items
we crash when we try to access the freed dentrys.

The patch just adds a check for if a rmdir has been done above
us and if so just does the unlink part of unregistration.

Sorry if you are getting this multiple times. I thouhgt I sent
this to some of you and lkml, but I do not see it.

Signed-off-by: default avatarMike Christie <>
Cc: Christoph Hellwig <>
Cc: Joel Becker <>
Signed-off-by: default avatarChristoph Hellwig <>
parent 1823342a
......@@ -1777,6 +1777,16 @@ void configfs_unregister_group(struct config_group *group)
struct dentry *dentry = group->cg_item.ci_dentry;
struct dentry *parent = group->cg_item.ci_parent->ci_dentry;
if (!group->cg_item.ci_parent->ci_group) {
* The parent has already been unlinked and detached
* due to a rmdir.
goto unlink_group;
inode_lock_nested(d_inode(parent), I_MUTEX_PARENT);
configfs_detach_prep(dentry, NULL);
......@@ -1791,6 +1801,7 @@ void configfs_unregister_group(struct config_group *group)
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