Re: general protection fault in __rds_rdma_map

[Santosh Shilimkar]

On 11/27/2017 10:30 AM, syzbot wrote:
> Hello,
>
> syzkaller hit the following crash on 
> e1d1ea549b57790a3d8cf6300e6ef86118d692a3
> git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/master
> compiler: gcc (GCC) 7.1.1 20170620
> .config is attached
> Raw console output is attached.
> C reproducer is attached
> syzkaller reproducer is attached. See 
> https://urldefense.proofpoint.com/v2/url?u=https-3A__goo.gl_kgGztJ&d=DwIBaQ&c=RoP1YumCXCgaWHvlZYR8PZh8Bv7qIrMUB65eapI_JnE&r=hWpFvp_cTkkwMMULcvbV65orOO9Gv3OUaY0ATWhQwak&m=0pw38xYdDB2QuLTkc6b0N3240iyzMU13jwFZvLaxDSo&s=0kx55ufXFnBORomS71r4MtXomSqMRKhkHI1tGM3oPic&e= 
>
> for information about syzkaller reproducers
>
>
> kasan: GPF could be caused by NULL-ptr deref or user memory access
> general protection fault: 0000 [#1] SMP KASAN
> RDS: rds_bind could not find a transport for 224.0.0.2, load rds_tcp or 
> rds_rdma?

Seems like the RDMA operation got triggered on the non RDMA transport
lead to non populated rs->rs_transport->get_mr(). Also seems like the
tests was running in the namespace and the RDMA transport doesn't
yet support it. Thanks for reporting. Will look into fix internally.

Regards,
Santosh