On 12/18/2017 12:43 AM, syzbot wrote:

quoted

Hello,
syzkaller hit the following crash on
6084b576dca2e898f5c101baef151f7bfdbb606d
git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/master
compiler: gcc (GCC) 7.1.1 20170620
.config is attached
Raw console output is attached.
Unfortunately, I don't have any reproducer for this bug yet.
BUG: unable to handle kernel NULL pointer dereference at
0000000000000028
program syz-executor6 is using a deprecated SCSI ioctl, please convert
it to SG_IO
IP: rds_send_xmit+0x80/0x930 net/rds/send.c:186

Looks like another one tripping on empty transport. Mostly below
should
address it but we will test it if it does.

diff --git a/net/rds/send.c b/net/rds/send.c
index 7244d2e..e2d0eaa 100644
--- a/net/rds/send.c
+++ b/net/rds/send.c

@@ -183,7 +183,7 @@ int rds_send_xmit(struct rds_conn_path *cp)
                goto out;
        }

-       if (conn->c_trans->xmit_path_prepare)
+       if (conn->c_trans && conn->c_trans->xmit_path_prepare)
                conn->c_trans->xmit_path_prepare(cp);