[PATCH] nvme-tcp: don't access released socket during error recovery

[Akinobu Mita <akinobu.mita@gmail.com>]

While the error recovery work is temporarily failing reconnect attempts,
running the 'nvme list' command causes a kernel NULL pointer dereference
by calling getsockname() with a released socket.

During error recovery work, the nvme tcp socket is released and a new one
created, so it is not safe to access the socket without proper check.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Fixes: 02c57a82c008 ("nvme-tcp: print actual source IP address through sysfs "address" attr")
Cc: Martin Belanger <martin.belanger@dell.com>
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: Chaitanya Kulkarni <kch@nvidia.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Keith Busch <kbusch@kernel.org>
Cc: Jens Axboe <axboe@fb.com>
Cc: Hannes Reinecke <hare@suse.de>
---
 drivers/nvme/host/tcp.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
index 1955c0ec209e..7723a4989524 100644
--- a/drivers/nvme/host/tcp.c
+++ b/drivers/nvme/host/tcp.c
@@ -2492,6 +2492,10 @@ static int nvme_tcp_get_address(struct nvme_ctrl *ctrl, char *buf, int size)
 
 	len = nvmf_get_address(ctrl, buf, size);
 
+	mutex_lock(&queue->queue_lock);
+
+	if (!test_bit(NVME_TCP_Q_LIVE, &queue->flags))
+		goto done;
 	ret = kernel_getsockname(queue->sock, (struct sockaddr *)&src_addr);
 	if (ret > 0) {
 		if (len > 0)
@@ -2499,6 +2503,8 @@ static int nvme_tcp_get_address(struct nvme_ctrl *ctrl, char *buf, int size)
 		len += scnprintf(buf + len, size - len, "%ssrc_addr=%pISc\n",
 				(len) ? "," : "", &src_addr);
 	}
+done:
+	mutex_unlock(&queue->queue_lock);
 
 	return len;
 }
-- 
2.34.1