From: Miklos Szeredi <miklos@szeredi.hu>
To: matthew@wil.cx
Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: DoS with POSIX file locks?
Date: Mon, 20 Mar 2006 13:52:39 +0100 [thread overview]
Message-ID: <E1FLJsF-0008A7-00@dorka.pomaz.szeredi.hu> (raw)
In-Reply-To: <20060320123950.GF8980@parisc-linux.org> (message from Matthew Wilcox on Mon, 20 Mar 2006 05:39:50 -0700)
> Right. Um. I took it out back in March 2003 after enough people
> convinced me it wasn't worth trying to account for all the memory
> processes use, and the userbeans project would take care of it anyway.
> Haha.
>
> It's hard to fix the accounting. You have to deal with one thread
> allocating the lock, and then a different thread freeing it. We never
> actually accounted for posix locks (which are the ones we really needed
> to!) and on occasion had current->locks go negative, with all kinds of
> associated badness.
Things look fairly straightforward if the accounting is done in
files_struct instead of task_struct. At least for POSIX locks. I
haven't looked at flocks or leases yet.
steal_locks() might cause problems, but that function should be gotten
rid of anyway.
Miklos
next prev parent reply other threads:[~2006-03-20 12:52 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-03-20 11:41 DoS with POSIX file locks? Miklos Szeredi
2006-03-20 12:11 ` Matthew Wilcox
2006-03-20 12:19 ` Miklos Szeredi
2006-03-20 12:39 ` Matthew Wilcox
2006-03-20 12:52 ` Miklos Szeredi [this message]
2006-03-20 13:13 ` Arjan van de Ven
2006-03-20 13:24 ` Miklos Szeredi
2006-03-20 13:30 ` Arjan van de Ven
2006-03-20 13:39 ` Miklos Szeredi
2006-03-20 15:32 ` Matthew Wilcox
2006-03-20 16:41 ` Miklos Szeredi
2006-03-20 20:35 ` J. Bruce Fields
2006-03-21 6:38 ` Miklos Szeredi
2006-03-20 18:22 ` Trond Myklebust
2006-03-21 9:44 ` Miklos Szeredi
2006-03-21 17:28 ` Trond Myklebust
2006-03-21 17:58 ` Miklos Szeredi
2006-03-21 18:16 ` Trond Myklebust
2006-03-21 19:16 ` Chris Wright
2006-03-22 6:21 ` Miklos Szeredi
2006-03-22 11:12 ` Trond Myklebust
2006-03-22 12:16 ` Miklos Szeredi
2006-03-22 15:56 ` Trond Myklebust
2006-03-22 16:34 ` Miklos Szeredi
2006-03-22 20:07 ` Trond Myklebust
2006-03-22 20:19 ` Miklos Szeredi
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