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authorD. Wythe <alibuda@linux.alibaba.com>2023-03-08 09:17:12 +0100
committerJakub Kicinski <kuba@kernel.org>2023-03-14 00:03:58 +0100
commit22a825c541d775c1dbe7b2402786025acad6727b (patch)
treede9a699ecc429220f9173bb439d3a13b39f44844 /net/smc
parentbnxt_en: reset PHC frequency in free-running mode (diff)
downloadlinux-22a825c541d775c1dbe7b2402786025acad6727b.tar.xz
linux-22a825c541d775c1dbe7b2402786025acad6727b.zip
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. Fixes: 0b29ec643613 ("net/smc: immediate termination for SMCR link groups") Signed-off-by: D. Wythe <alibuda@linux.alibaba.com> Reviewed-by: Tony Lu <tonylu@linux.alibaba.com> Reviewed-by: Wenjia Zhang <wenjia@linux.ibm.com> Link: https://lore.kernel.org/r/1678263432-17329-1-git-send-email-alibuda@linux.alibaba.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/smc')
-rw-r--r--net/smc/smc_cdc.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/net/smc/smc_cdc.c b/net/smc/smc_cdc.c
index 53f63bfbaf5f..89105e95b452 100644
--- a/net/smc/smc_cdc.c
+++ b/net/smc/smc_cdc.c
@@ -114,6 +114,9 @@ int smc_cdc_msg_send(struct smc_connection *conn,
union smc_host_cursor cfed;
int rc;
+ if (unlikely(!READ_ONCE(conn->sndbuf_desc)))
+ return -ENOBUFS;
+
smc_cdc_add_pending_send(conn, pend);
conn->tx_cdc_seq++;