> -----Original Message-----
> From: linux-rdma-owner@xxxxxxxxxxxxxxx <linux-rdma-
> owner@xxxxxxxxxxxxxxx> On Behalf Of Myungho Jung
> Sent: Friday, January 4, 2019 12:46 AM
> To: Doug Ledford <dledford@xxxxxxxxxx>; Jason Gunthorpe <jgg@xxxxxxxx>
> Cc: linux-rdma@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> Subject: [PATCH] RDMA/cma: Rollback source IP address if failing to acquire
> device
>
> If cma_acquire_dev_by_src_ip() returns error in addr_handler(), the device
> state changes back to RDMA_CM_ADDR_BOUND but the resolved source IP
> address is still left. After that, if rdma_destroy_id() is called after
> rdma_listen(), the device is freed without removed from listen_any_list in
> cma_cancel_operation(). Revert to the previous IP address if acquiring device
> fails.
>
> Reported-by: syzbot+f3ce716af730c8f96637@xxxxxxxxxxxxxxxxxxxxxxxxx
> Signed-off-by: Myungho Jung <mhjungk@xxxxxxxxx>
> ---
> drivers/infiniband/core/cma.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c
> index 63a7cc00bae0..d27c3b154e71 100644
> --- a/drivers/infiniband/core/cma.c
> +++ b/drivers/infiniband/core/cma.c
> @@ -2963,13 +2963,17 @@ static void addr_handler(int status, struct
> sockaddr *src_addr, {
> struct rdma_id_private *id_priv = context;
> struct rdma_cm_event event = {};
> + struct sockaddr *addr;
> + struct sockaddr_storage old_addr;
>
> mutex_lock(&id_priv->handler_mutex);
> if (!cma_comp_exch(id_priv, RDMA_CM_ADDR_QUERY,
> RDMA_CM_ADDR_RESOLVED))
> goto out;
>
> - memcpy(cma_src_addr(id_priv), src_addr,
> rdma_addr_size(src_addr));
> + addr = cma_src_addr(id_priv);
> + memcpy(&old_addr, addr, rdma_addr_size(addr));
Please add a comment here in the patch, why we need to store the old src address and restore back.
/*
* Store the previous src address, so that if we fail to acquire matching rdma device,
* old address can be restored back, which helps to cancel the cma listen operation
* correctly.
*/
> + memcpy(addr, src_addr, rdma_addr_size(src_addr));
> if (!status && !id_priv->cma_dev) {
> status = cma_acquire_dev_by_src_ip(id_priv);
> if (status)
> @@ -2980,6 +2984,8 @@ static void addr_handler(int status, struct sockaddr
> *src_addr,
> }
>
> if (status) {
> + memcpy(addr, &old_addr,
> + rdma_addr_size((struct sockaddr *)&old_addr));
> if (!cma_comp_exch(id_priv, RDMA_CM_ADDR_RESOLVED,
> RDMA_CM_ADDR_BOUND))
> goto out;
> --
> 2.17.1
Reviewed-by: Parav Pandit <parav@xxxxxxxxxxxx>
