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From:   Xingyuan Mo <hdthky0@gmail.com>
To:     chuck.lever@oracle.com, jlayton@kernel.org
Cc:     linux-nfs@vger.kernel.org, dai.ngo@oracle.com,
        Xingyuan Mo <hdthky0@gmail.com>
Subject: [PATCH] NFSD: fix use-after-free in nfsd4_ssc_setup_dul()
Date:   Thu, 12 Jan 2023 00:24:53 +0800
Message-Id: <20230111162453.8295-1-hdthky0@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

If signal_pending() returns true, schedule_timeout() will not be executed,
causing the waiting task to remain in the wait queue.
Fixed by adding a call to finish_wait(), which ensures that the waiting
task will always be removed from the wait queue.

Reported-by: Xingyuan Mo <hdthky0@gmail.com>
Signed-off-by: Xingyuan Mo <hdthky0@gmail.com>
---
 fs/nfsd/nfs4proc.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index bd880d55f565..3fa819e29b3f 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -1318,6 +1318,7 @@ static __be32 nfsd4_ssc_setup_dul(struct nfsd_net *nn, char *ipaddr,
 			/* allow 20secs for mount/unmount for now - revisit */
 			if (signal_pending(current) ||
 					(schedule_timeout(20*HZ) == 0)) {
+				finish_wait(&nn->nfsd_ssc_waitq, &wait);
 				kfree(work);
 				return nfserr_eagain;
 			}
-- 
2.34.1