From: Theodore Ts'o <tytso@mit.edu>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Sparse Mailing-list <linux-sparse@vger.kernel.org>
Subject: Re: What does this sparse warning mean in posix_acl.h?
Date: Sat, 17 Aug 2013 16:55:54 -0400 [thread overview]
Message-ID: <20130817205554.GH30769@thunk.org> (raw)
In-Reply-To: <CA+55aFxeSzQuF7RR5jDcwwGeL0XFTRsLWe+X0=ybVPAsAkggBA@mail.gmail.com>
On Sat, Aug 17, 2013 at 09:16:54AM -0700, Linus Torvalds wrote:
> On Sat, Aug 17, 2013 at 7:28 AM, Theodore Ts'o <tytso@thunk.org> wrote:
> >
> > It apparently has something to do with rcu and "address spaces" but I'm
> > not completely sure what sparse is complaining about --- and whether it
> > is a false positive or a bug in the posix_acl.h.
>
> I guess we should mark i_acl and i_defauly_acl to be RCU-accessed, and
> then annotate all the accesses properly.
I may be missing something, but it looks like the ACL code isn't
following the RCU rules at _all_. Even with the missing
rcu_derference() macro invocations which you added in your
proof-of-concept patch, we're still missing the rcu_read_lock() calls
around the use of the rcu pointers.
If so, I'm kind of wondering why we haven't noticed massive problems
here before.
- Ted
next prev parent reply other threads:[~2013-08-17 20:55 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-17 14:28 What does this sparse warning mean in posix_acl.h? Theodore Ts'o
2013-08-17 16:16 ` Linus Torvalds
2013-08-17 20:55 ` Theodore Ts'o [this message]
2013-08-17 21:14 ` Linus Torvalds
2013-08-17 21:23 ` Theodore Ts'o
2013-08-17 21:31 ` Linus Torvalds
2013-08-17 21:23 ` Linus Torvalds
2013-08-17 16:17 ` Josh Triplett
2013-08-17 16:33 ` Linus Torvalds
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