This is a note to let you know that I've just added the patch titled
audit: fix refcounting in audit-tree
to the 3.0-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
audit-fix-refcounting-in-audit-tree.patch
and it can be found in the queue-3.0 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From a2140fc0cb0325bb6384e788edd27b9a568714e2 Mon Sep 17 00:00:00 2001
From: Miklos Szeredi <[email protected]>
Date: Wed, 15 Aug 2012 12:55:22 +0200
Subject: audit: fix refcounting in audit-tree
From: Miklos Szeredi <[email protected]>
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 <[email protected]>
Reported-by: Valentin Avram <[email protected]>
Reported-by: Peter Moody <[email protected]>
Acked-by: Eric Paris <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
kernel/audit_tree.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
--- a/kernel/audit_tree.c
+++ b/kernel/audit_tree.c
@@ -256,7 +256,6 @@ 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;
}
@@ -299,7 +298,6 @@ 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:
@@ -338,6 +336,7 @@ static int create_chunk(struct inode *in
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;
@@ -418,6 +417,7 @@ static int tag_chunk(struct inode *inode
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);
@@ -451,7 +451,6 @@ static int tag_chunk(struct inode *inode
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;
}
Patches currently in stable-queue which might be from [email protected] are
queue-3.0/audit-fix-refcounting-in-audit-tree.patch
queue-3.0/audit-don-t-free_chunk-after-fsnotify_add_mark.patch
queue-3.0/vfs-canonicalize-create-mode-in-build_open_flags.patch
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