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[3.5.y.z,extended,stable] Patch "NFS: Fix a delegation callback race" has been added to staging queue

Message ID 1394708444-10883-1-git-send-email-luis.henriques@canonical.com
State New
Headers show

Commit Message

Luis Henriques March 13, 2014, 11 a.m. UTC
This is a note to let you know that I have just added a patch titled

    NFS: Fix a delegation callback race

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

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From 8c7f1f0820cb27638e4430aad909635f87423da5 Mon Sep 17 00:00:00 2001
From: Trond Myklebust <trond.myklebust@primarydata.com>
Date: Sun, 2 Mar 2014 22:03:12 -0500
Subject: NFS: Fix a delegation callback race

commit 755a48a7a4eb05b9c8424e3017d947b2961a60e0 upstream.

The clean-up in commit 36281caa839f ended up removing a NULL pointer check
that is needed in order to prevent an Oops in
nfs_async_inode_return_delegation().

Reported-by: "Yan, Zheng" <zheng.z.yan@intel.com>
Link: http://lkml.kernel.org/r/5313E9F6.2020405@intel.com
Fixes: 36281caa839f (NFSv4: Further clean-ups of delegation stateid validation)
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
---
 fs/nfs/delegation.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

--
1.9.0
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Patch

diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c
index bd3a960..04cae5c 100644
--- a/fs/nfs/delegation.c
+++ b/fs/nfs/delegation.c
@@ -548,16 +548,19 @@  int nfs_async_inode_return_delegation(struct inode *inode,

 	rcu_read_lock();
 	delegation = rcu_dereference(NFS_I(inode)->delegation);
+	if (delegation == NULL)
+		goto out_enoent;

-	if (!clp->cl_mvops->match_stateid(&delegation->stateid, stateid)) {
-		rcu_read_unlock();
-		return -ENOENT;
-	}
+	if (!clp->cl_mvops->match_stateid(&delegation->stateid, stateid))
+		goto out_enoent;
 	nfs_mark_return_delegation(server, delegation);
 	rcu_read_unlock();

 	nfs_delegation_run_state_manager(clp);
 	return 0;
+out_enoent:
+	rcu_read_unlock();
+	return -ENOENT;
 }

 static struct inode *