linux-kernel - [PATCH AUTOSEL 5.4 16/25] nvmet-tcp: fix a race condition between release_queue and io

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Date:   Tue, 30 Nov 2021 09:51:46 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Maurizio Lombardi <mlombard@...hat.com>,
        Keith Busch <kbusch@...nel.org>,
        Sagi Grimberg <sagi@...mberg.me>,
        John Meneghini <jmeneghi@...hat.com>,
        Christoph Hellwig <hch@....de>,
        Sasha Levin <sashal@...nel.org>, kch@...dia.com,
        linux-nvme@...ts.infradead.org
Subject: [PATCH AUTOSEL 5.4 16/25] nvmet-tcp: fix a race condition between release_queue and io_work

From: Maurizio Lombardi <mlombard@...hat.com>

[ Upstream commit a208fc56721775987c1b86e20d86d7e0d017c0b2 ]

If the initiator executes a reset controller operation while
performing I/O, the target kernel will crash because of a race condition
between release_queue and io_work;
nvmet_tcp_uninit_data_in_cmds() may be executed while io_work
is running, calling flush_work() was not sufficient to
prevent this because io_work could requeue itself.

Fix this bug by using cancel_work_sync() to prevent io_work
from requeuing itself and set rcv_state to NVMET_TCP_RECV_ERR to
make sure we don't receive any more data from the socket.

Signed-off-by: Maurizio Lombardi <mlombard@...hat.com>
Reviewed-by: Keith Busch <kbusch@...nel.org>
Reviewed-by: Sagi Grimberg <sagi@...mberg.me>
Reviewed-by: John Meneghini <jmeneghi@...hat.com>
Signed-off-by: Christoph Hellwig <hch@....de>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/nvme/target/tcp.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/nvme/target/tcp.c b/drivers/nvme/target/tcp.c
index fac1985870765..b3e82b0889f0b 100644
--- a/drivers/nvme/target/tcp.c
+++ b/drivers/nvme/target/tcp.c
@@ -1352,7 +1352,9 @@ static void nvmet_tcp_release_queue_work(struct work_struct *w)
 	mutex_unlock(&nvmet_tcp_queue_mutex);
 
 	nvmet_tcp_restore_socket_callbacks(queue);
-	flush_work(&queue->io_work);
+	cancel_work_sync(&queue->io_work);
+	/* stop accepting incoming data */
+	queue->rcv_state = NVMET_TCP_RECV_ERR;
 
 	nvmet_tcp_uninit_data_in_cmds(queue);
 	nvmet_sq_destroy(&queue->nvme_sq);
-- 
2.33.0