net/smc: fix shutdown in state SMC_LISTEN

[ Upstream commit 1255fcb2a655f05e02f3a74675a6d6525f187afd ]

Calling shutdown with SHUT_RD and SHUT_RDWR for a listening SMC socket
crashes, because
   commit 127f49705823 ("net/smc: release clcsock from tcp_listen_worker")
releases the internal clcsock in smc_close_active() and sets smc->clcsock
to NULL.
For SHUT_RD the smc_close_active() call is removed.
For SHUT_RDWR the kernel_sock_shutdown() call is omitted, since the
clcsock is already released.

Fixes: 127f49705823 ("net/smc: release clcsock from tcp_listen_worker")
Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Reported-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index a6d604f..f9c289e 100644 (file)
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -1203,14 +1203,12 @@ static int smc_shutdown(struct socket *sock, int how)
                rc = smc_close_shutdown_write(smc);
                break;
        case SHUT_RD:
-               if (sk->sk_state == SMC_LISTEN)
-                       rc = smc_close_active(smc);
-               else
-                       rc = 0;
-                       /* nothing more to do because peer is not involved */
+               rc = 0;
+               /* nothing more to do because peer is not involved */
                break;
        }
-       rc1 = kernel_sock_shutdown(smc->clcsock, how);
+       if (smc->clcsock)
+               rc1 = kernel_sock_shutdown(smc->clcsock, how);
        /* map sock_shutdown_cmd constants to sk_shutdown value range */
        sk->sk_shutdown |= how + 1;