net/smc: Stop the CLC flow if no link to map buffers on
authorWen Gu <guwen@linux.alibaba.com>
Tue, 20 Sep 2022 06:43:09 +0000 (14:43 +0800)
committerPaolo Abeni <pabeni@redhat.com>
Thu, 22 Sep 2022 10:53:53 +0000 (12:53 +0200)
commite738455b2c6dcdab03e45d97de36476f93f557d2
tree2f7c8c0ff7053292a39fdfdaa61300f62e54df5c
parent624aea6bede7fef24dc3daed83f37453c11ebb39
net/smc: Stop the CLC flow if no link to map buffers on

There might be a potential race between SMC-R buffer map and
link group termination.

smc_smcr_terminate_all()     | smc_connect_rdma()
--------------------------------------------------------------
                             | smc_conn_create()
for links in smcibdev        |
        schedule links down  |
                             | smc_buf_create()
                             |  \- smcr_buf_map_usable_links()
                             |      \- no usable links found,
                             |         (rmb->mr = NULL)
                             |
                             | smc_clc_send_confirm()
                             |  \- access conn->rmb_desc->mr[]->rkey
                             |     (panic)

During reboot and IB device module remove, all links will be set
down and no usable links remain in link groups. In such situation
smcr_buf_map_usable_links() should return an error and stop the
CLC flow accessing to uninitialized mr.

Fixes: b9247544c1bc ("net/smc: convert static link ID instances to support multiple links")
Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
Link: https://lore.kernel.org/r/1663656189-32090-1-git-send-email-guwen@linux.alibaba.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
net/smc/smc_core.c