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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        syzbot+228a82b263b5da91883d@syzkaller.appspotmail.com,
        Benjamin Coddington <bcodding@redhat.com>,
        Anna Schumaker <Anna.Schumaker@Netapp.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.19 276/276] NFS: Fix a double unlock from nfs_match,get_client
Date:   Wed, 29 May 2019 20:07:14 -0700
Message-Id: <20190530030542.445869259@linuxfoundation.org>
In-Reply-To: <20190530030523.133519668@linuxfoundation.org>
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[ Upstream commit c260121a97a3e4df6536edbc2f26e166eff370ce ]

Now that nfs_match_client drops the nfs_client_lock, we should be
careful
to always return it in the same condition: locked.

Fixes: 950a578c6128 ("NFS: make nfs_match_client killable")
Reported-by: syzbot+228a82b263b5da91883d@syzkaller.appspotmail.com
Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/nfs/client.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index 846d45cb1a3c8..c092661147b30 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -305,9 +305,9 @@ static struct nfs_client *nfs_match_client(const struct nfs_client_initdata *dat
 			spin_unlock(&nn->nfs_client_lock);
 			error = nfs_wait_client_init_complete(clp);
 			nfs_put_client(clp);
+			spin_lock(&nn->nfs_client_lock);
 			if (error < 0)
 				return ERR_PTR(error);
-			spin_lock(&nn->nfs_client_lock);
 			goto again;
 		}
 
-- 
2.20.1