This is a note to let you know that I've just added the patch titled
virtio_net: Fix napi_skb_cache_put warning
to the 6.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
virtio_net-fix-napi_skb_cache_put-warning.patch
and it can be found in the queue-6.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 05b8d464fac54971f36a274ea61d6c8f7a23fe58
Author: Breno Leitao <leitao@xxxxxxxxxx>
Date: Fri Jul 12 04:53:25 2024 -0700
virtio_net: Fix napi_skb_cache_put warning
[ Upstream commit f8321fa75102246d7415a6af441872f6637c93ab ]
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>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index b1f8b720733e5..cd254a1fd88ec 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -2341,7 +2341,7 @@ static int virtnet_receive(struct receive_queue *rq, int budget,
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);
@@ -2359,7 +2359,7 @@ static void virtnet_poll_cleantx(struct receive_queue *rq)
do {
virtqueue_disable_cb(sq->vq);
- free_old_xmit(sq, txq, true);
+ free_old_xmit(sq, txq, !!budget);
} while (unlikely(!virtqueue_enable_cb_delayed(sq->vq)));
if (sq->vq->num_free >= 2 + MAX_SKB_FRAGS) {
@@ -2403,7 +2403,7 @@ static int virtnet_poll(struct napi_struct *napi, int budget)
unsigned int xdp_xmit = 0;
bool napi_complete;
- virtnet_poll_cleantx(rq);
+ virtnet_poll_cleantx(rq, budget);
received = virtnet_receive(rq, budget, &xdp_xmit);
rq->packets_in_napi += received;
@@ -2518,7 +2518,7 @@ static int virtnet_poll_tx(struct napi_struct *napi, int budget)
txq = netdev_get_tx_queue(vi->dev, index);
__netif_tx_lock(txq, raw_smp_processor_id());
virtqueue_disable_cb(sq->vq);
- free_old_xmit(sq, txq, true);
+ free_old_xmit(sq, txq, !!budget);
if (sq->vq->num_free >= 2 + MAX_SKB_FRAGS) {
if (netif_tx_queue_stopped(txq)) {
