[EXTERNAL] [PATCH v5 3/4] eal/linux: report uevent socket overrun

[Long Li]

> 
> Make uevent handler handle case where kernel netlink receive buffer is
> overrun. If this happens the DPDK device state will potentially be out of sync,
> but better not to give up.
> 
> The code already handles the case of kernel sending a zero length message; it
> just ignores it.
> 
> Fixes: 0d0f478d0483 ("eal/linux: add uevent parse and process")
> Cc: stable at dpdk.org
> 
> Reported-by: Randy Tice <rtice at cisco.com>
> Signed-off-by: Stephen Hemminger <stephen at networkplumber.org>

Reviewed-by: Long Li <longli at microsoft.com>


> ---
>  lib/eal/linux/eal_dev.c | 19 ++++++++++++++-----
>  1 file changed, 14 insertions(+), 5 deletions(-)
> 
> diff --git a/lib/eal/linux/eal_dev.c b/lib/eal/linux/eal_dev.c index
> fb5c8bf070..b535122ff6 100644
> --- a/lib/eal/linux/eal_dev.c
> +++ b/lib/eal/linux/eal_dev.c
> @@ -270,11 +270,20 @@ dev_uev_handler(__rte_unused void *param)
> 
>  	ret = recv(rte_intr_fd_get(intr_handle), buf, EAL_UEV_MSG_LEN,
>  		   MSG_DONTWAIT);
> -	if (ret < 0 && errno == EAGAIN)
> -		return;
> -	else if (ret <= 0) {
> -		/* connection is closed or broken, can not up again. */
> -		EAL_LOG(ERR, "uevent socket connection is broken.");
> +	if (ret < 0) {
> +		/* transient error */
> +		if (errno == EAGAIN || errno == EWOULDBLOCK || errno ==
> EINTR)
> +			return;
> +
> +		/* kernel netlink messages lost */
> +		if (errno == ENOBUFS) {
> +			EAL_LOG(NOTICE, "kernel receive buffer overrun");
> +			return;
> +		}
> +
> +		EAL_LOG(ERR, "unexpected error on uevent recv: %s",
> +			strerror(errno));
> +
>  		rte_eal_alarm_set(1, dev_delayed_unregister, NULL);
>  		return;
>  	}
> --
> 2.53.0