| From b4fb4cc5ba83b20dae13cef116c33648e81d2f44 Mon Sep 17 00:00:00 2001 |
| From: Parav Pandit <parav@mellanox.com> |
| Date: Sun, 26 Jan 2020 16:26:46 +0200 |
| Subject: RDMA/cma: Fix unbalanced cm_id reference count during address resolve |
| |
| From: Parav Pandit <parav@mellanox.com> |
| |
| commit b4fb4cc5ba83b20dae13cef116c33648e81d2f44 upstream. |
| |
| Below commit missed the AF_IB and loopback code flow in |
| rdma_resolve_addr(). This leads to an unbalanced cm_id refcount in |
| cma_work_handler() which puts the refcount which was not incremented prior |
| to queuing the work. |
| |
| A call trace is observed with such code flow: |
| |
| BUG: unable to handle kernel NULL pointer dereference at (null) |
| [<ffffffff96b67e16>] __mutex_lock_slowpath+0x166/0x1d0 |
| [<ffffffff96b6715f>] mutex_lock+0x1f/0x2f |
| [<ffffffffc0beabb5>] cma_work_handler+0x25/0xa0 |
| [<ffffffff964b9ebf>] process_one_work+0x17f/0x440 |
| [<ffffffff964baf56>] worker_thread+0x126/0x3c0 |
| |
| Hence, hold the cm_id reference when scheduling the resolve work item. |
| |
| Fixes: 722c7b2bfead ("RDMA/{cma, core}: Avoid callback on rdma_addr_cancel()") |
| Link: https://lore.kernel.org/r/20200126142652.104803-2-leon@kernel.org |
| Signed-off-by: Parav Pandit <parav@mellanox.com> |
| Signed-off-by: Leon Romanovsky <leonro@mellanox.com> |
| Reviewed-by: Jason Gunthorpe <jgg@mellanox.com> |
| Signed-off-by: Jason Gunthorpe <jgg@mellanox.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| drivers/infiniband/core/cma.c | 2 ++ |
| 1 file changed, 2 insertions(+) |
| |
| --- a/drivers/infiniband/core/cma.c |
| +++ b/drivers/infiniband/core/cma.c |
| @@ -3091,6 +3091,7 @@ static int cma_resolve_loopback(struct r |
| rdma_addr_get_sgid(&id_priv->id.route.addr.dev_addr, &gid); |
| rdma_addr_set_dgid(&id_priv->id.route.addr.dev_addr, &gid); |
| |
| + atomic_inc(&id_priv->refcount); |
| cma_init_resolve_addr_work(work, id_priv); |
| queue_work(cma_wq, &work->work); |
| return 0; |
| @@ -3117,6 +3118,7 @@ static int cma_resolve_ib_addr(struct rd |
| rdma_addr_set_dgid(&id_priv->id.route.addr.dev_addr, (union ib_gid *) |
| &(((struct sockaddr_ib *) &id_priv->id.route.addr.dst_addr)->sib_addr)); |
| |
| + atomic_inc(&id_priv->refcount); |
| cma_init_resolve_addr_work(work, id_priv); |
| queue_work(cma_wq, &work->work); |
| return 0; |