In the Linux kernel, the following vulnerability has been resolved:

net/smc: fix NULL sndbuf_desc in smc_cdc_tx_handler()

When performing a stress test on SMC-R by rmmod mlx5_ib driver
during the wrk/nginx test, we found that there is a probability
of triggering a panic while terminating all link groups.

This issue dues to the race between smc_smcr_terminate_all()
and smc_buf_create().

			smc_smcr_terminate_all

smc_buf_create
/* init */
conn->sndbuf_desc = NULL;
...

			__smc_lgr_terminate
				smc_conn_kill
					smc_close_abort
						smc_cdc_get_slot_and_msg_send

			__softirqentry_text_start
				smc_wr_tx_process_cqe
					smc_cdc_tx_handler
						READ(conn->sndbuf_desc->len);
						/* panic dues to NULL sndbuf_desc */

conn->sndbuf_desc = xxx;

This patch tries to fix the issue by always to check the sndbuf_desc
before send any cdc msg, to make sure that no null pointer is
seen during cqe processing.

https://git.kernel.org/stable/c/22a825c541d775c1dbe7b2402786025acad6727b

https://git.kernel.org/stable/c/31817c530768b0199771ec6019571b4f0ddbf230

https://git.kernel.org/stable/c/3c270435db8aa34929263dddae8fd050f5216ecb

https://git.kernel.org/stable/c/3ebac7cf0a184a8102821a7a00203f02bebda83c

https://git.kernel.org/stable/c/b108bd9e6be000492ebebe867daa699285978a10