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| author | Miklos Szeredi <mszeredi@suse.cz> | 2012-08-15 12:55:22 +0200 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2012-09-12 03:37:02 +0100 |
| commit | c2cc94c67ca8e3c496a790d631fd1ac38d31d522 (patch) | |
| tree | aa869ece80fa85df0fcb08ed6f56a4a9b80624dd /kernel/audit_tree.c | |
| parent | 7d78916c93c07eedb9cf37f5b09e62fbd65968cc (diff) | |
| download | linux-stable-c2cc94c67ca8e3c496a790d631fd1ac38d31d522.tar.gz linux-stable-c2cc94c67ca8e3c496a790d631fd1ac38d31d522.tar.bz2 linux-stable-c2cc94c67ca8e3c496a790d631fd1ac38d31d522.zip | |
audit: fix refcounting in audit-tree
commit a2140fc0cb0325bb6384e788edd27b9a568714e2 upstream.
Refcounting of fsnotify_mark in audit tree is broken. E.g:
refcount
create_chunk
alloc_chunk 1
fsnotify_add_mark 2
untag_chunk
fsnotify_get_mark 3
fsnotify_destroy_mark
audit_tree_freeing_mark 2
fsnotify_put_mark 1
fsnotify_put_mark 0
via destroy_list
fsnotify_mark_destroy -1
This was reported by various people as triggering Oops when stopping auditd.
We could just remove the put_mark from audit_tree_freeing_mark() but that would
break freeing via inode destruction. So this patch simply omits a put_mark
after calling destroy_mark or adds a get_mark before.
The additional get_mark is necessary where there's no other put_mark after
fsnotify_destroy_mark() since it assumes that the caller is holding a reference
(or the inode is keeping the mark pinned, not the case here AFAICS).
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Reported-by: Valentin Avram <aval13@gmail.com>
Reported-by: Peter Moody <pmoody@google.com>
Acked-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'kernel/audit_tree.c')
| -rw-r--r-- | kernel/audit_tree.c | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/kernel/audit_tree.c b/kernel/audit_tree.c index d52d247b07a5..31fdc480b5c6 100644 --- a/kernel/audit_tree.c +++ b/kernel/audit_tree.c @@ -250,7 +250,6 @@ static void untag_chunk(struct node *p) spin_unlock(&hash_lock); spin_unlock(&entry->lock); fsnotify_destroy_mark(entry); - fsnotify_put_mark(entry); goto out; } @@ -293,7 +292,6 @@ static void untag_chunk(struct node *p) spin_unlock(&hash_lock); spin_unlock(&entry->lock); fsnotify_destroy_mark(entry); - fsnotify_put_mark(entry); goto out; Fallback: @@ -332,6 +330,7 @@ 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; @@ -412,6 +411,7 @@ 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); @@ -445,7 +445,6 @@ static int tag_chunk(struct inode *inode, struct audit_tree *tree) spin_unlock(&old_entry->lock); fsnotify_destroy_mark(old_entry); fsnotify_put_mark(old_entry); /* pair to fsnotify_find mark_entry */ - fsnotify_put_mark(old_entry); /* and kill it */ return 0; } |