net/smc: fix NULL sndbuf_desc in smc_cdc_tx_handler()

Summary

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.

Timeline

1. May 2, 2025, 3:55 PM UTCCVE published
2. Oct 15, 2026, 9:33 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: yes · Technical impact: partial

3. Oct 15, 2026, 9:41 PM UTCRecord last updated

Affected versions

• Linux Linux

  From 0b29ec6436138721acf5844e558f7334a0fa61d5 · fixed in 31817c530768b0199771ec6019571b4f0ddbf230; From 0b29ec6436138721acf5844e558f7334a0fa61d5 · fixed in b108bd9e6be000492ebebe867daa699285978a10; From 0b29ec6436138721acf5844e558f7334a0fa61d5 · fixed in 3c270435db8aa34929263dddae8fd050f5216ecb; From 0b29ec6436138721acf5844e558f7334a0fa61d5 · fixed in 3ebac7cf0a184a8102821a7a00203f02bebda83c; From 0b29ec6436138721acf5844e558f7334a0fa61d5 · fixed in 22a825c541d775c1dbe7b2402786025acad6727b

• Linux Linux

  5.5

• KernelLinux

  From 5.5.0 · fixed in 5.10.176; From 5.11.0 · fixed in 5.15.104; From 5.16.0 · fixed in 6.1.21; From 6.2.0 · fixed in 6.2.8

References 5