linux-kernel - Re: nfsv2 ref leak in 2.6.24?

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Sat, 20 Oct 2007 13:12:31 -0400
From:	Trond Myklebust <trond.myklebust@....uio.no>
To:	Erez Zadok <ezk@...sunysb.edu>
Cc:	bfields@...ldses.org, nfs@...ts.sourceforge.net, neilb@...e.de,
	linux-kernel@...r.kernel.org
Subject: Re: nfsv2 ref leak in 2.6.24?


On Fri, 2007-10-19 at 22:33 -0400, Erez Zadok wrote:
> Trond, good news.  I was able to narrow down the problem to purely the
> client-side, probably dcache/readdir related, and I have a shell script that
> deterministically triggers the problem each time for me (this is a FC6 image
> under Vmware 6.0.1).  Here's a short shell script which reliably triggers
> the "lost files" problem -- I create a file via nfs2 on the client side, and
> sometimes it doesn't show up in readdir, but it is there if you stat it
> directly.

Ah... I got confused as to what you were measuring and where. Looking at
nfs_proc_create(), there is indeed a missing call to
nfs_mark_for_revalidate(). The reason why you need such a call being the
usual one: NFSv2 doesn't provide post-op attributes for the directory.

The patch below ought to fix the problem.

Cheers
  Trond
---------------------- CUT HERE -----------------------
From: Trond Myklebust <Trond.Myklebust@...app.com>
Date: Sat, 20 Oct 2007 13:07:21 -0400
NFSv2: Ensure that the directory metadata gets revalidated on file create

Signed-off-by: Trond Myklebust <Trond.Myklebust@...app.com>
---

 fs/nfs/proc.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/fs/nfs/proc.c b/fs/nfs/proc.c
index 97669ed..4f80d88 100644
--- a/fs/nfs/proc.c
+++ b/fs/nfs/proc.c
@@ -211,6 +211,7 @@ nfs_proc_create(struct inode *dir, struct dentry *dentry, struct iattr *sattr,
 	nfs_fattr_init(&fattr);
 	dprintk("NFS call  create %s\n", dentry->d_name.name);
 	status = rpc_call_sync(NFS_CLIENT(dir), &msg, 0);
+	nfs_mark_for_revalidate(dir);
 	if (status == 0)
 		status = nfs_instantiate(dentry, &fhandle, &fattr);
 	dprintk("NFS reply create: %d\n", status);


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/