Re: [PATCH] migration/rdma: Fix cm_event used before being initialized

[Dr. David Alan Gilbert]

* Li Zhijian (lizhijian@cn.fujitsu.com) wrote:
> A segmentation fault was triggered when i try to abort a postcopy + rdma
> migration.
> 
> since rdma_ack_cm_event releases a uninitialized cm_event in thise case.
> 
> like below:
> 2496     ret = rdma_get_cm_event(rdma->channel, &cm_event);
> 2497     if (ret) {
> 2498         perror("rdma_get_cm_event after rdma_connect");
> 2499         ERROR(errp, "connecting to destination!");
> 2500         rdma_ack_cm_event(cm_event); <<<< cause segmentation fault
> 2501         goto err_rdma_source_connect;
> 2502     }
> 
> Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>

OK, that's an easy fix then; but I wonder if we should perhaps remove
that rdma_ack_cm_event, if it's the get_cm_event that's failed?

Still,


Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

> ---
>  migration/rdma.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/migration/rdma.c b/migration/rdma.c
> index 00eac34232..2dadb62aed 100644
> --- a/migration/rdma.c
> +++ b/migration/rdma.c
> @@ -2466,7 +2466,7 @@ static int qemu_rdma_connect(RDMAContext *rdma, Error 
> **errp)
>                                            .private_data = &cap,
>                                            .private_data_len = sizeof(cap),
>                                          };
> -    struct rdma_cm_event *cm_event;
> +    struct rdma_cm_event *cm_event = NULL;
>      int ret;
>  
>      /*
> -- 
> 2.30.2
> 
> 
> 
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK