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authorTejun Heo <tj@kernel.org>2014-01-17 18:58:25 +0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-01-17 23:50:07 +0400
commitdb4aad209bc9aefd91f0a9aeb9e37364088b39ad (patch)
tree28cc941640469a11111808a6e77be61e892e5041 /fs/kernfs/symlink.c
parent917f56caaabc215f9658006dad28a9665ec0ce19 (diff)
downloadlinux-db4aad209bc9aefd91f0a9aeb9e37364088b39ad.tar.xz
kernfs: associate a new kernfs_node with its parent on creation
Once created, a kernfs_node is always destroyed by kernfs_put(). Since ba7443bc656e ("sysfs, kernfs: implement kernfs_create/destroy_root()"), kernfs_put() depends on kernfs_root() to locate the ino_ida. kernfs_root() in turn depends on kernfs_node->parent being set for !dir nodes. This means that kernfs_put() of a !dir node requires its ->parent to be initialized. This leads to oops when a newly created !dir node is destroyed without going through kernfs_add_one() or after failing kernfs_add_one() before ->parent is set. kernfs_root() invoked from kernfs_put() will try to dereference NULL parent. Fix it by moving parent association to kernfs_new_node() from kernfs_add_one(). kernfs_new_node() now takes @parent instead of @root and determines the root from the parent and also sets the new node's parent properly. @parent parameter is removed from kernfs_add_one(). As there's no parent when creating the root node, __kernfs_new_node() which takes @root as before and doesn't set the parent is used in that case. This ensures that a kernfs_node in any stage in its life has its parent associated and thus can be put. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/kernfs/symlink.c')
-rw-r--r--fs/kernfs/symlink.c5
1 files changed, 2 insertions, 3 deletions
diff --git a/fs/kernfs/symlink.c b/fs/kernfs/symlink.c
index a03e26036ef9..4d457055acb9 100644
--- a/fs/kernfs/symlink.c
+++ b/fs/kernfs/symlink.c
@@ -30,8 +30,7 @@ struct kernfs_node *kernfs_create_link(struct kernfs_node *parent,
struct kernfs_addrm_cxt acxt;
int error;
- kn = kernfs_new_node(kernfs_root(parent), name, S_IFLNK|S_IRWXUGO,
- KERNFS_LINK);
+ kn = kernfs_new_node(parent, name, S_IFLNK|S_IRWXUGO, KERNFS_LINK);
if (!kn)
return ERR_PTR(-ENOMEM);
@@ -41,7 +40,7 @@ struct kernfs_node *kernfs_create_link(struct kernfs_node *parent,
kernfs_get(target); /* ref owned by symlink */
kernfs_addrm_start(&acxt);
- error = kernfs_add_one(&acxt, kn, parent);
+ error = kernfs_add_one(&acxt, kn);
kernfs_addrm_finish(&acxt);
if (!error)