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-rw-r--r--kernel/audit_tree.c91
1 files changed, 54 insertions, 37 deletions
diff --git a/kernel/audit_tree.c b/kernel/audit_tree.c
index 8ba0e0d934f..8b509441f49 100644
--- a/kernel/audit_tree.c
+++ b/kernel/audit_tree.c
@@ -24,6 +24,7 @@ struct audit_chunk {
struct list_head trees; /* with root here */
int dead;
int count;
+ atomic_long_t refs;
struct rcu_head head;
struct node {
struct list_head list;
@@ -56,7 +57,8 @@ static LIST_HEAD(prune_list);
* tree is refcounted; one reference for "some rules on rules_list refer to
* it", one for each chunk with pointer to it.
*
- * chunk is refcounted by embedded inotify_watch.
+ * chunk is refcounted by embedded inotify_watch + .refs (non-zero refcount
+ * of watch contributes 1 to .refs).
*
* node.index allows to get from node.list to containing chunk.
* MSB of that sucker is stolen to mark taggings that we might have to
@@ -121,6 +123,7 @@ static struct audit_chunk *alloc_chunk(int count)
INIT_LIST_HEAD(&chunk->hash);
INIT_LIST_HEAD(&chunk->trees);
chunk->count = count;
+ atomic_long_set(&chunk->refs, 1);
for (i = 0; i < count; i++) {
INIT_LIST_HEAD(&chunk->owners[i].list);
chunk->owners[i].index = i;
@@ -129,9 +132,8 @@ static struct audit_chunk *alloc_chunk(int count)
return chunk;
}
-static void __free_chunk(struct rcu_head *rcu)
+static void free_chunk(struct audit_chunk *chunk)
{
- struct audit_chunk *chunk = container_of(rcu, struct audit_chunk, head);
int i;
for (i = 0; i < chunk->count; i++) {
@@ -141,14 +143,16 @@ static void __free_chunk(struct rcu_head *rcu)
kfree(chunk);
}
-static inline void free_chunk(struct audit_chunk *chunk)
+void audit_put_chunk(struct audit_chunk *chunk)
{
- call_rcu(&chunk->head, __free_chunk);
+ if (atomic_long_dec_and_test(&chunk->refs))
+ free_chunk(chunk);
}
-void audit_put_chunk(struct audit_chunk *chunk)
+static void __put_chunk(struct rcu_head *rcu)
{
- put_inotify_watch(&chunk->watch);
+ struct audit_chunk *chunk = container_of(rcu, struct audit_chunk, head);
+ audit_put_chunk(chunk);
}
enum {HASH_SIZE = 128};
@@ -176,7 +180,7 @@ struct audit_chunk *audit_tree_lookup(const struct inode *inode)
list_for_each_entry_rcu(p, list, hash) {
if (p->watch.inode == inode) {
- get_inotify_watch(&p->watch);
+ atomic_long_inc(&p->refs);
return p;
}
}
@@ -194,17 +198,49 @@ int audit_tree_match(struct audit_chunk *chunk, struct audit_tree *tree)
/* tagging and untagging inodes with trees */
-static void untag_chunk(struct audit_chunk *chunk, struct node *p)
+static struct audit_chunk *find_chunk(struct node *p)
+{
+ int index = p->index & ~(1U<<31);
+ p -= index;
+ return container_of(p, struct audit_chunk, owners[0]);
+}
+
+static void untag_chunk(struct node *p)
{
+ struct audit_chunk *chunk = find_chunk(p);
struct audit_chunk *new;
struct audit_tree *owner;
int size = chunk->count - 1;
int i, j;
+ if (!pin_inotify_watch(&chunk->watch)) {
+ /*
+ * Filesystem is shutting down; all watches are getting
+ * evicted, just take it off the node list for this
+ * tree and let the eviction logics take care of the
+ * rest.
+ */
+ owner = p->owner;
+ if (owner->root == chunk) {
+ list_del_init(&owner->same_root);
+ owner->root = NULL;
+ }
+ list_del_init(&p->list);
+ p->owner = NULL;
+ put_tree(owner);
+ return;
+ }
+
+ spin_unlock(&hash_lock);
+
+ /*
+ * pin_inotify_watch() succeeded, so the watch won't go away
+ * from under us.
+ */
mutex_lock(&chunk->watch.inode->inotify_mutex);
if (chunk->dead) {
mutex_unlock(&chunk->watch.inode->inotify_mutex);
- return;
+ goto out;
}
owner = p->owner;
@@ -221,7 +257,7 @@ static void untag_chunk(struct audit_chunk *chunk, struct node *p)
inotify_evict_watch(&chunk->watch);
mutex_unlock(&chunk->watch.inode->inotify_mutex);
put_inotify_watch(&chunk->watch);
- return;
+ goto out;
}
new = alloc_chunk(size);
@@ -263,7 +299,7 @@ static void untag_chunk(struct audit_chunk *chunk, struct node *p)
inotify_evict_watch(&chunk->watch);
mutex_unlock(&chunk->watch.inode->inotify_mutex);
put_inotify_watch(&chunk->watch);
- return;
+ goto out;
Fallback:
// do the best we can
@@ -277,6 +313,9 @@ Fallback:
put_tree(owner);
spin_unlock(&hash_lock);
mutex_unlock(&chunk->watch.inode->inotify_mutex);
+out:
+ unpin_inotify_watch(&chunk->watch);
+ spin_lock(&hash_lock);
}
static int create_chunk(struct inode *inode, struct audit_tree *tree)
@@ -387,13 +426,6 @@ static int tag_chunk(struct inode *inode, struct audit_tree *tree)
return 0;
}
-static struct audit_chunk *find_chunk(struct node *p)
-{
- int index = p->index & ~(1U<<31);
- p -= index;
- return container_of(p, struct audit_chunk, owners[0]);
-}
-
static void kill_rules(struct audit_tree *tree)
{
struct audit_krule *rule, *next;
@@ -431,17 +463,10 @@ static void prune_one(struct audit_tree *victim)
spin_lock(&hash_lock);
while (!list_empty(&victim->chunks)) {
struct node *p;
- struct audit_chunk *chunk;
p = list_entry(victim->chunks.next, struct node, list);
- chunk = find_chunk(p);
- get_inotify_watch(&chunk->watch);
- spin_unlock(&hash_lock);
-
- untag_chunk(chunk, p);
- put_inotify_watch(&chunk->watch);
- spin_lock(&hash_lock);
+ untag_chunk(p);
}
spin_unlock(&hash_lock);
put_tree(victim);
@@ -469,7 +494,6 @@ static void trim_marked(struct audit_tree *tree)
while (!list_empty(&tree->chunks)) {
struct node *node;
- struct audit_chunk *chunk;
node = list_entry(tree->chunks.next, struct node, list);
@@ -477,14 +501,7 @@ static void trim_marked(struct audit_tree *tree)
if (!(node->index & (1U<<31)))
break;
- chunk = find_chunk(node);
- get_inotify_watch(&chunk->watch);
- spin_unlock(&hash_lock);
-
- untag_chunk(chunk, node);
-
- put_inotify_watch(&chunk->watch);
- spin_lock(&hash_lock);
+ untag_chunk(node);
}
if (!tree->root && !tree->goner) {
tree->goner = 1;
@@ -878,7 +895,7 @@ static void handle_event(struct inotify_watch *watch, u32 wd, u32 mask,
static void destroy_watch(struct inotify_watch *watch)
{
struct audit_chunk *chunk = container_of(watch, struct audit_chunk, watch);
- free_chunk(chunk);
+ call_rcu(&chunk->head, __put_chunk);
}
static const struct inotify_operations rtree_inotify_ops = {