From 755a48a7a4eb05b9c8424e3017d947b2961a60e0 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Sun, 2 Mar 2014 22:03:12 -0500 Subject: [PATCH] NFS: Fix a delegation callback race 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" Link: http://lkml.kernel.org/r/5313E9F6.2020405@intel.com Fixes: 36281caa839f (NFSv4: Further clean-ups of delegation stateid validation) Cc: stable@vger.kernel.org # 3.4+ Signed-off-by: Trond Myklebust --- fs/nfs/delegation.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c index ef792f29f831..5d8ccecf5f5c 100644 --- a/fs/nfs/delegation.c +++ b/fs/nfs/delegation.c @@ -659,16 +659,19 @@ 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 * -- 2.20.1