> -----Original Message-----
> From: Jason Gunthorpe <[email protected]>
> Sent: Thursday, August 23, 2018 9:55 AM
> To: Eric Biggers <[email protected]>
> Cc: Doug Ledford <[email protected]>; [email protected];
> [email protected]; Leon Romanovsky
> <[email protected]>; [email protected]; Mark Bloch
> <[email protected]>; Moni Shoua <[email protected]>; Parav Pandit
> <[email protected]>; [email protected]; syzbot
> <[email protected]>
> Subject: Re: [RDMA bug] KASAN: use-after-free Read in __list_del_entry_valid
> (4)
>
> On Wed, Aug 22, 2018 at 11:16:31PM -0700, Eric Biggers wrote:
> > Hello RDMA / InfiniBand maintainers,
> >
> > This is an RDMA bug and it still occurs on Linus' tree as of today
> > (commit 815f0ddb346c1960).
> >
> > I've also simplified the reproducer for it; see below after the original
> > report.
> > Apparently it involves a race between RDMA_USER_CM_CMD_RESOLVE_IP
> and
> > RDMA_USER_CM_CMD_LISTEN.
>
> That is an amazing reproducer!
>
> I have a feeling this is the same cause as all the other syzkaller bugs in
> this code:
> lack of any sane locking at all :\
>
> We've talked about chucking a big lock around this whole thing, but nobody has
> done it yet.. It isn't so simple.
>
I had some code in which reduces three locks (handler_lock, qp_mutex, id_lock)
to single mutex to protect the cm_id and protects every exported symbol of
rdmacm which works on cm_id.
But not ready enough to post it as patch yet. Lot of tests required before I
get there and some refactor too before that.
> Jason
