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

[Yann Droneaud <ydroneaud-RlY5vtjFyJ3QT0dZR+AlfA@public.gmane.org>]

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


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