From b3e8692b4dde5cf5fc60e4b95385229a72623182 Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Wed, 15 Aug 2012 12:55:22 +0200 Subject: audit: clean up refcounting in audit-tree Drop the initial reference by fsnotify_init_mark early instead of audit_tree_freeing_mark() at destroy time. In the cases we destroy the mark before we drop the initial reference we need to get rid of the get_mark that balances the put_mark in audit_tree_freeing_mark(). Signed-off-by: Miklos Szeredi --- kernel/audit_tree.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) (limited to 'kernel/audit_tree.c') diff --git a/kernel/audit_tree.c b/kernel/audit_tree.c index 2b2ffff9eca2..ed206fd88cca 100644 --- a/kernel/audit_tree.c +++ b/kernel/audit_tree.c @@ -292,6 +292,7 @@ static void untag_chunk(struct node *p) spin_unlock(&hash_lock); spin_unlock(&entry->lock); fsnotify_destroy_mark(entry); + fsnotify_put_mark(&new->mark); /* drop initial reference */ goto out; Fallback: @@ -330,7 +331,6 @@ static int create_chunk(struct inode *inode, struct audit_tree *tree) spin_unlock(&hash_lock); chunk->dead = 1; spin_unlock(&entry->lock); - fsnotify_get_mark(entry); fsnotify_destroy_mark(entry); fsnotify_put_mark(entry); return 0; @@ -346,6 +346,7 @@ static int create_chunk(struct inode *inode, struct audit_tree *tree) insert_hash(chunk); spin_unlock(&hash_lock); spin_unlock(&entry->lock); + fsnotify_put_mark(entry); /* drop initial reference */ return 0; } @@ -411,7 +412,6 @@ static int tag_chunk(struct inode *inode, struct audit_tree *tree) spin_unlock(&chunk_entry->lock); spin_unlock(&old_entry->lock); - fsnotify_get_mark(chunk_entry); fsnotify_destroy_mark(chunk_entry); fsnotify_put_mark(chunk_entry); @@ -444,6 +444,7 @@ static int tag_chunk(struct inode *inode, struct audit_tree *tree) spin_unlock(&chunk_entry->lock); spin_unlock(&old_entry->lock); fsnotify_destroy_mark(old_entry); + fsnotify_put_mark(chunk_entry); /* drop initial reference */ fsnotify_put_mark(old_entry); /* pair to fsnotify_find mark_entry */ return 0; } @@ -915,7 +916,12 @@ static void audit_tree_freeing_mark(struct fsnotify_mark *entry, struct fsnotify struct audit_chunk *chunk = container_of(entry, struct audit_chunk, mark); evict_chunk(chunk); - fsnotify_put_mark(entry); + + /* + * We are guaranteed to have at least one reference to the mark from + * either the inode or the caller of fsnotify_destroy_mark(). + */ + BUG_ON(atomic_read(&entry->refcnt) < 1); } static bool audit_tree_send_event(struct fsnotify_group *group, struct inode *inode, -- cgit v1.2.3-59-g8ed1b