On 22.09.22 10:29, Wen Gu wrote:
On 2022/9/20 14:43, Wen Gu wrote:
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@xxxxxxxxxxxxxxxxx>
---
net/smc/smc_core.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c
index ebf56cd..df89c2e 100644
--- a/net/smc/smc_core.c
+++ b/net/smc/smc_core.c
@@ -2239,7 +2239,7 @@ static struct smc_buf_desc
*smcr_new_buf_create(struct smc_link_group *lgr,
static int smcr_buf_map_usable_links(struct smc_link_group *lgr,
struct smc_buf_desc *buf_desc, bool is_rmb)
{
- int i, rc = 0;
+ int i, rc = 0, cnt = 0;
/* protect against parallel link reconfiguration */
mutex_lock(&lgr->llc_conf_mutex);
@@ -2252,9 +2252,12 @@ static int smcr_buf_map_usable_links(struct
smc_link_group *lgr,
rc = -ENOMEM;
goto out;
}
+ cnt++;
}
out:
mutex_unlock(&lgr->llc_conf_mutex);
+ if (!rc && !cnt)
+ rc = -EINVAL;
return rc;
}
Any comments or reviews are welcome and appreciated.
Thanks,
Wen Gu
Sorry for the late answer!
Good catch! Thank you!
Acked-by: Wenjia Zhang <wenjia@xxxxxxxxxxxxx>
