Re: [PATCH RE-RESEND V2 for-next 3/5] IB/core: Call ib_unregister_mad_agent() only for valid agents

Yann Droneaud
2015-02-16T21:28:12Z

Le jeudi 05 février 2015 à 13:53 +0200, Or Gerlitz a écrit :
> From: Majd Dibbiny <majd-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
>
> In some error flows, ib_mad_unregister_agent is being invoked also in cases where
^^^^^^^^^^^^^^^^^^^^^^^
ib_unregister_mad_agent()

> the ib_mad_register_agent call failed (resulting in an illegal pointer in the
^^^^^^^^^^^^^^^^^^^^^
ib_register_mad_agent()

> agent field). This causes a kernel crash in the error flow.
>
> Fix this by calling ib_unregister_mad_agent only for cases where
> ib_register_mad_agent succeeded.
>

The code was checking for struct ib_mad_agent *agent not being NULL,
while ib_register_mad_agent() returns a ERR_PTR() in case of error
... bad :(

> Signed-off-by: Majd Dibbiny <majd-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
> Signed-off-by: Or Gerlitz <ogerlitz-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
> ---
> drivers/infiniband/hw/mlx4/mad.c | 2 +-
> drivers/infiniband/hw/mthca/mthca_mad.c | 2 +-
> drivers/infiniband/hw/qib/qib_mad.c | 2 +-
> 3 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/infiniband/hw/mlx4/mad.c b/drivers/infiniband/hw/mlx4/mad.c
> index 82a7dd8..6be0d2c 100644
> --- a/drivers/infiniband/hw/mlx4/mad.c
> +++ b/drivers/infiniband/hw/mlx4/mad.c
> @@ -907,7 +907,7 @@ int mlx4_ib_mad_init(struct mlx4_ib_dev *dev)
> err:
> for (p = 0; p < dev->num_ports; ++p)
> for (q = 0; q <= 1; ++q)
> - if (dev->send_agent[p][q])
> + if (!IS_ERR(dev->send_agent[p][q]))
> ib_unregister_mad_agent(dev->send_agent[p][q]);
>
> return ret;
> diff --git a/drivers/infiniband/hw/mthca/mthca_mad.c b/drivers/infiniband/hw/mthca/mthca_mad.c
> index 8881fa3..5f1a7ce 100644
> --- a/drivers/infiniband/hw/mthca/mthca_mad.c
> +++ b/drivers/infiniband/hw/mthca/mthca_mad.c
> @@ -317,7 +317,7 @@ int mthca_create_agents(struct mthca_dev *dev)
> err:
> for (p = 0; p < dev->limits.num_ports; ++p)
> for (q = 0; q <= 1; ++q)
> - if (dev->send_agent[p][q])
> + if (!IS_ERR(dev->send_agent[p][q]))
> ib_unregister_mad_agent(dev->send_agent[p][q]);
>
> return ret;
> diff --git a/drivers/infiniband/hw/qib/qib_mad.c b/drivers/infiniband/hw/qib/qib_mad.c
> index 636be11..6c7cc80 100644
> --- a/drivers/infiniband/hw/qib/qib_mad.c
> +++ b/drivers/infiniband/hw/qib/qib_mad.c
> @@ -2499,7 +2499,7 @@ int qib_create_agents(struct qib_ibdev *dev)
> err:
> for (p = 0; p < dd->num_pports; p++) {
> ibp = &dd->pport[p].ibport_data;
> - if (ibp->send_agent) {
> + if (!IS_ERR(ibp->send_agent)) {
> agent = ibp->send_agent;
> ibp->send_agent = NULL;
> ib_unregister_mad_agent(agent);

Regards.

--
Yann Droneaud
OPTEYA