[PATCH 5.18 528/879] net/smc: fix listen processing for SMC-Rv2

Greg Kroah-Hartman
2022-06-08T00:38:43Z

From: liuyacan <liuyacan@corp.netease.com>

[ Upstream commit 8c3b8dc5cc9bf6d273ebe18b16e2d6882bcfb36d ]

In the process of checking whether RDMAv2 is available, the current
implementation first sets ini->smcrv2.ib_dev_v2, and then allocates
smc buf desc, but the latter may fail. Unfortunately, the caller
will only check the former. In this case, a NULL pointer reference
will occur in smc_clc_send_confirm_accept() when accessing
conn->rmb_desc.

This patch does two things:
1. Use the return code to determine whether V2 is available.
2. If the return code is NODEV, continue to check whether V1 is
available.

Fixes: e49300a6bf62 ("net/smc: add listen processing for SMC-Rv2")
Signed-off-by: liuyacan <liuyacan@corp.netease.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/smc/af_smc.c | 44 +++++++++++++++++++++++++++-----------------
1 file changed, 27 insertions(+), 17 deletions(-)

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index 45a24d24210f..d3de54b70c05 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -2093,13 +2093,13 @@ static int smc_listen_rdma_reg(struct smc_sock *new_smc, bool local_first)
return 0;
}

-static void smc_find_rdma_v2_device_serv(struct smc_sock *new_smc,
- struct smc_clc_msg_proposal *pclc,
- struct smc_init_info *ini)
+static int smc_find_rdma_v2_device_serv(struct smc_sock *new_smc,
+ struct smc_clc_msg_proposal *pclc,
+ struct smc_init_info *ini)
{
struct smc_clc_v2_extension *smc_v2_ext;
u8 smcr_version;
- int rc;
+ int rc = 0;

if (!(ini->smcr_version & SMC_V2) || !smcr_indicated(ini->smc_type_v2))
goto not_found;
@@ -2117,26 +2117,31 @@ static void smc_find_rdma_v2_device_serv(struct smc_sock *new_smc,
ini->smcrv2.saddr = new_smc->clcsock->sk->sk_rcv_saddr;
ini->smcrv2.daddr = smc_ib_gid_to_ipv4(smc_v2_ext->roce);
rc = smc_find_rdma_device(new_smc, ini);
- if (rc) {
- smc_find_ism_store_rc(rc, ini);
+ if (rc)
goto not_found;
- }
+
if (!ini->smcrv2.uses_gateway)
memcpy(ini->smcrv2.nexthop_mac, pclc->lcl.mac, ETH_ALEN);

smcr_version = ini->smcr_version;
ini->smcr_version = SMC_V2;
rc = smc_listen_rdma_init(new_smc, ini);
- if (!rc)
- rc = smc_listen_rdma_reg(new_smc, ini->first_contact_local);
- if (!rc)
- return;
- ini->smcr_version = smcr_version;
- smc_find_ism_store_rc(rc, ini);
+ if (rc) {
+ ini->smcr_version = smcr_version;
+ goto not_found;
+ }
+ rc = smc_listen_rdma_reg(new_smc, ini->first_contact_local);
+ if (rc) {
+ ini->smcr_version = smcr_version;
+ goto not_found;
+ }
+ return 0;

not_found:
+ rc = rc ?: SMC_CLC_DECL_NOSMCDEV;
ini->smcr_version &= ~SMC_V2;
ini->check_smcrv2 = false;
+ return rc;
}

static int smc_find_rdma_v1_device_serv(struct smc_sock *new_smc,
@@ -2169,6 +2174,7 @@ static int smc_listen_find_device(struct smc_sock *new_smc,
struct smc_init_info *ini)
{
int prfx_rc;
+ int rc;

/* check for ISM device matching V2 proposed device */
smc_find_ism_v2_device_serv(new_smc, pclc, ini);
@@ -2196,14 +2202,18 @@ static int smc_listen_find_device(struct smc_sock *new_smc,
return ini->rc ?: SMC_CLC_DECL_NOSMCDDEV;

/* check if RDMA V2 is available */
- smc_find_rdma_v2_device_serv(new_smc, pclc, ini);
- if (ini->smcrv2.ib_dev_v2)
+ rc = smc_find_rdma_v2_device_serv(new_smc, pclc, ini);
+ if (!rc)
return 0;

+ /* skip V1 check if V2 is unavailable for non-Device reason */
+ if (rc != SMC_CLC_DECL_NOSMCDEV &&
+ rc != SMC_CLC_DECL_NOSMCRDEV &&
+ rc != SMC_CLC_DECL_NOSMCDDEV)
+ return rc;
+
/* check if RDMA V1 is available */
if (!prfx_rc) {
- int rc;
-
rc = smc_find_rdma_v1_device_serv(new_smc, pclc, ini);
smc_find_ism_store_rc(rc, ini);
return (!rc) ? 0 : ini->rc;
--
2.35.1