From: Dave Chinner <david@fromorbit.com>
To: Eric Paris <eparis@redhat.com>
Cc: linux-kernel@vger.kernel.org,
linux-security-module@vger.kernel.org,
linux-fsdevel@vger.kernel.org, hch@infradead.org,
zohar@us.ibm.com, warthog9@kernel.org, jmorris@namei.org,
kyle@mcmartin.ca, hpa@zytor.com, akpm@linux-foundation.org,
torvalds@linux-foundation.org, mingo@elte.hu,
viro@zeniv.linux.org.uk
Subject: Re: [PATCH 5/6] IMA: use rbtree instead of radix tree for inode information cache
Date: Wed, 20 Oct 2010 10:17:47 +1100 [thread overview]
Message-ID: <20101019231747.GC12506@dastard> (raw)
In-Reply-To: <20101019225839.12396.92630.stgit@paris.rdu.redhat.com>
On Tue, Oct 19, 2010 at 06:58:39PM -0400, Eric Paris wrote:
> @@ -36,12 +63,11 @@ struct ima_iint_cache *ima_iint_find_get(struct inode *inode)
> struct ima_iint_cache *iint;
>
> rcu_read_lock();
> - iint = radix_tree_lookup(&ima_iint_store, (unsigned long)inode);
> - if (!iint)
> - goto out;
> - kref_get(&iint->refcount);
> -out:
> + iint = __ima_iint_find(inode);
> + if (iint)
> + kref_get(&iint->refcount);
> rcu_read_unlock();
> +
This is wrong - the rbtree is protected only by the ima_iint_lock(),
not RCU. Hence you can't do lockless lookups on an rbtree in this
manner as they will race with inserts and deletes.
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
next prev parent reply other threads:[~2010-10-19 23:19 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-19 22:58 [PATCH 1/6] IMA: move read/write counters into struct inode Eric Paris
2010-10-19 22:58 ` [PATCH 2/6] IMA: drop the inode opencount since it isn't needed for operation Eric Paris
2010-10-19 22:58 ` [PATCH 3/6] IMA: use unsigned int instead of long for counters Eric Paris
2010-10-19 22:58 ` [PATCH 4/6] IMA: only allocate iint when needed Eric Paris
2010-10-20 3:53 ` Al Viro
2010-10-19 22:58 ` [PATCH 5/6] IMA: use rbtree instead of radix tree for inode information cache Eric Paris
2010-10-19 23:17 ` Dave Chinner [this message]
2010-10-20 11:31 ` Peter Zijlstra
2010-10-20 22:05 ` Dave Chinner
2010-10-20 22:22 ` Linus Torvalds
2010-10-20 22:47 ` Trond Myklebust
2010-10-21 0:58 ` Linus Torvalds
2010-10-21 2:17 ` Dave Chinner
2010-10-19 22:58 ` [PATCH 6/6] IMA: use i_writecount rather than a private counter Eric Paris
2010-10-20 0:25 ` [PATCH 1/6] IMA: move read/write counters into struct inode Linus Torvalds
2010-10-20 0:25 ` Linus Torvalds
2010-10-23 3:01 ` Eric Paris
2010-10-24 6:52 ` Mimi Zohar
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