From 1bf9116d0866a649104a5dfa008c302ad54d1e02 Mon Sep 17 00:00:00 2001 From: Jesper Dangaard Brouer Date: Wed, 8 Aug 2018 23:00:45 +0200 Subject: [PATCH] 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: 389ab7f01af9 ("xdp: introduce xdp_return_frame_rx_napi") Fixes: 735fc4054b3a ("xdp: change ndo_xdp_xmit API to support bulking") Signed-off-by: Jesper Dangaard Brouer Signed-off-by: Daniel Borkmann --- kernel/bpf/devmap.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c index d361fc1e3bf3..750d45edae79 100644 --- a/kernel/bpf/devmap.c +++ b/kernel/bpf/devmap.c @@ -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 */ - xdp_return_frame_rx_napi(xdpf); + 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); } } }