6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Breno Leitao <leitao@xxxxxxxxxx>
commit f8321fa75102246d7415a6af441872f6637c93ab upstream.
After the commit bdacf3e34945 ("net: Use nested-BH locking for
napi_alloc_cache.") was merged, the following warning began to appear:
WARNING: CPU: 5 PID: 1 at net/core/skbuff.c:1451 napi_skb_cache_put+0x82/0x4b0
__warn+0x12f/0x340
napi_skb_cache_put+0x82/0x4b0
napi_skb_cache_put+0x82/0x4b0
report_bug+0x165/0x370
handle_bug+0x3d/0x80
exc_invalid_op+0x1a/0x50
asm_exc_invalid_op+0x1a/0x20
__free_old_xmit+0x1c8/0x510
napi_skb_cache_put+0x82/0x4b0
__free_old_xmit+0x1c8/0x510
__free_old_xmit+0x1c8/0x510
__pfx___free_old_xmit+0x10/0x10
The issue arises because virtio is assuming it's running in NAPI context
even when it's not, such as in the netpoll case.
To resolve this, modify virtnet_poll_tx() to only set NAPI when budget
is available. Same for virtnet_poll_cleantx(), which always assumed that
it was in a NAPI context.
Fixes: df133f3f9625 ("virtio_net: bulk free tx skbs")
Suggested-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Breno Leitao <leitao@xxxxxxxxxx>
Reviewed-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Acked-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
Acked-by: Jason Wang <jasowang@xxxxxxxxxx>
Reviewed-by: Heng Qi <hengqi@xxxxxxxxxxxxxxxxx>
Link: https://patch.msgid.link/20240712115325.54175-1-leitao@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
[Shivani: Modified to apply on v6.6.y]
Signed-off-by: Shivani Agarwal <shivani.agarwal@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/virtio_net.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -2140,7 +2140,7 @@ static int virtnet_receive(struct receiv
return packets;
}
-static void virtnet_poll_cleantx(struct receive_queue *rq)
+static void virtnet_poll_cleantx(struct receive_queue *rq, int budget)
{
struct virtnet_info *vi = rq->vq->vdev->priv;
unsigned int index = vq2rxq(rq->vq);
@@ -2158,7 +2158,7 @@ static void virtnet_poll_cleantx(struct
do {
virtqueue_disable_cb(sq->vq);
- free_old_xmit_skbs(sq, true);
+ free_old_xmit_skbs(sq, !!budget);
} while (unlikely(!virtqueue_enable_cb_delayed(sq->vq)));
if (sq->vq->num_free >= 2 + MAX_SKB_FRAGS)
@@ -2177,7 +2177,7 @@ static int virtnet_poll(struct napi_stru
unsigned int received;
unsigned int xdp_xmit = 0;
- virtnet_poll_cleantx(rq);
+ virtnet_poll_cleantx(rq, budget);
received = virtnet_receive(rq, budget, &xdp_xmit);
@@ -2280,7 +2280,7 @@ static int virtnet_poll_tx(struct napi_s
txq = netdev_get_tx_queue(vi->dev, index);
__netif_tx_lock(txq, raw_smp_processor_id());
virtqueue_disable_cb(sq->vq);
- free_old_xmit_skbs(sq, true);
+ free_old_xmit_skbs(sq, !!budget);
if (sq->vq->num_free >= 2 + MAX_SKB_FRAGS)
netif_tx_wake_queue(txq);
