net/smc: fix listen processing for SMC-Rv2

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>

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index 45a24d24210f0996b458d59e4b043ffec73c5a82..d3de54b70c0511bdc73256a19400a423338bb80c 100644 (file)
--- 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;