Messages in this thread | | | Date | Thu, 23 Aug 2018 11:17:32 -0600 | From | Jason Gunthorpe <> | Subject | Re: [RDMA bug] KASAN: use-after-free Read in __list_del_entry_valid (4) |
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On Thu, Aug 23, 2018 at 04:39:29PM +0000, Parav Pandit wrote: > > > > From: Jason Gunthorpe <jgg@ziepe.ca> > > Sent: Thursday, August 23, 2018 9:55 AM > > To: Eric Biggers <ebiggers@kernel.org> > > Cc: Doug Ledford <dledford@redhat.com>; linux-rdma@vger.kernel.org; > > dasaratharaman.chandramouli@intel.com; Leon Romanovsky > > <leonro@mellanox.com>; linux-kernel@vger.kernel.org; Mark Bloch > > <markb@mellanox.com>; Moni Shoua <monis@mellanox.com>; Parav Pandit > > <parav@mellanox.com>; syzkaller-bugs@googlegroups.com; syzbot > > <syzbot+29ee8f76017ce6cf03da@syzkaller.appspotmail.com> > > 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.
That does sound promising..
Jason
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