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Commit 1bf9116d authored by Jesper Dangaard Brouer's avatar Jesper Dangaard Brouer Committed by Daniel Borkmann
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xdp: fix bug in devmap teardown code path 



Like cpumap teardown, the devmap teardown code also flush remaining
xdp_frames, via bq_xmit_all() in case map entry is removed.  The code
can call xdp_return_frame_rx_napi, from the the wrong context, in-case
ndo_xdp_xmit() fails.

Fixes: 389ab7f0 ("xdp: introduce xdp_return_frame_rx_napi")
Fixes: 735fc405 ("xdp: change ndo_xdp_xmit API to support bulking")
Signed-off-by: default avatarJesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parent 37d7ff25

kernel/bpf/devmap.c

+9 −5
Original line number Diff line number Diff line
@@ -217,7 +217,8 @@ void __dev_map_insert_ctx(struct bpf_map *map, u32 bit) 
}



static int bq_xmit_all(struct bpf_dtab_netdev *obj,

		       struct xdp_bulk_queue *bq, u32 flags)

		       struct xdp_bulk_queue *bq, u32 flags,

		       bool in_napi_ctx)

{

	struct net_device *dev = obj->dev;

	int sent = 0, drops = 0, err = 0;
@@ -254,7 +255,10 @@ static int bq_xmit_all(struct bpf_dtab_netdev *obj, 
		struct xdp_frame *xdpf = bq->q[i];



		/* RX path under NAPI protection, can return frames faster */

		if (likely(in_napi_ctx))

			xdp_return_frame_rx_napi(xdpf);

		else

			xdp_return_frame(xdpf);

		drops++;

	}

	goto out;
@@ -286,7 +290,7 @@ void __dev_map_flush(struct bpf_map *map) 
		__clear_bit(bit, bitmap);



		bq = this_cpu_ptr(dev->bulkq);

		bq_xmit_all(dev, bq, XDP_XMIT_FLUSH);

		bq_xmit_all(dev, bq, XDP_XMIT_FLUSH, true);

	}

}
@@ -316,7 +320,7 @@ static int bq_enqueue(struct bpf_dtab_netdev *obj, struct xdp_frame *xdpf, 
	struct xdp_bulk_queue *bq = this_cpu_ptr(obj->bulkq);



	if (unlikely(bq->count == DEV_MAP_BULK_SIZE))

		bq_xmit_all(obj, bq, 0);

		bq_xmit_all(obj, bq, 0, true);



	/* Ingress dev_rx will be the same for all xdp_frame's in

	 * bulk_queue, because bq stored per-CPU and must be flushed
@@ -385,7 +389,7 @@ static void dev_map_flush_old(struct bpf_dtab_netdev *dev) 
			__clear_bit(dev->bit, bitmap);



			bq = per_cpu_ptr(dev->bulkq, cpu);

			bq_xmit_all(dev, bq, XDP_XMIT_FLUSH);

			bq_xmit_all(dev, bq, XDP_XMIT_FLUSH, false);

		}

	}

}