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From: Juan Quintela <quintela@redhat.com>
In-Reply-To: <1433286850-12753-1-git-send-email-padmanabh.ratnakar@avagotech.com>
	(Padmanabh Ratnakar's message of "Wed, 3 Jun 2015 04:44:10 +0530")
References: <1433286850-12753-1-git-send-email-padmanabh.ratnakar@avagotech.com>
Date: Tue, 02 Jun 2015 14:57:37 +0200
Message-ID: <87pp5e9sji.fsf@neno.neno>
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Subject: Re: [Qemu-devel] [PATCH] rdma: Fix qemu crash when IPv6 address is
	used for migration
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To: Padmanabh Ratnakar <padmanabh.ratnakar@avagotech.com>
Cc: amit.shah@redhat.com, Meghana Cheripady <meghana.cheripady@avagotech.com>, qemu-devel@nongnu.org, mrhines@us.ibm.com

Padmanabh Ratnakar <padmanabh.ratnakar@avagotech.com> wrote:
> Qemu crashes when IPv6 address is specified for migration and access
> to any RDMA uverbs device available on the system is blocked using cgroups.
> Fix the crash by checking the return value of ibv_open_device routine.
>
> Signed-off-by: Meghana Cheripady <meghana.cheripady@avagotech.com>
> Signed-off-by: Padmanabh Ratnakar <padmanabh.ratnakar@avagotech.com>
> ---
>  migration/rdma.c |    7 +++++++
>  1 files changed, 7 insertions(+), 0 deletions(-)
>
> diff --git a/migration/rdma.c b/migration/rdma.c
> index 77e3444..3671903 100644
> --- a/migration/rdma.c
> +++ b/migration/rdma.c
> @@ -790,6 +790,13 @@ static int qemu_rdma_broken_ipv6_kernel(Error **errp, struct ibv_context *verbs)
>  
>          for (x = 0; x < num_devices; x++) {
>              verbs = ibv_open_device(dev_list[x]);
> +            if (!verbs) {
> +                if (errno == EPERM) {
> +                    continue;

Why do we want to continue here?


> +                } else {
> +                    return -EINVAL;
> +                }
> +            }
>  
>              if (ibv_query_port(verbs, 1, &port_attr)) {


Reading the documentation, my understandig is that if verbs is NULL, we
don't have a context to do anything useful here, no?

>                  ibv_close_device(verbs);


Thanks, Juan.