Commit bd2ddeb8 authored by Breno Leitao's avatar Breno Leitao Committed by Wen Zhiwei
Browse files

virtio_net: Fix napi_skb_cache_put warning 

stable inclusion
from stable-v6.6.50
commit f5e9a22d19bb98a7e86034db85eb295e94187caa
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/IAYKL6

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=f5e9a22d19bb98a7e86034db85eb295e94187caa



--------------------------------

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: df133f3f ("virtio_net: bulk free tx skbs")
Suggested-by: default avatarJakub Kicinski <kuba@kernel.org>
Signed-off-by: default avatarBreno Leitao <leitao@debian.org>
Reviewed-by: default avatarJakub Kicinski <kuba@kernel.org>
Acked-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Acked-by: default avatarJason Wang <jasowang@redhat.com>
Reviewed-by: default avatarHeng Qi <hengqi@linux.alibaba.com>
Link: https://patch.msgid.link/20240712115325.54175-1-leitao@debian.org


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
[Shivani: Modified to apply on v6.6.y]
Signed-off-by: default avatarShivani Agarwal <shivani.agarwal@broadcom.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarWen Zhiwei <wenzhiwei@kylinos.cn>
parent 59087e99

drivers/net/virtio_net.c

+4 −4
Original line number Diff line number Diff line
@@ -2140,7 +2140,7 @@ 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);
@@ -2158,7 +2158,7 @@ static void virtnet_poll_cleantx(struct receive_queue *rq) 


		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_struct *napi, int budget) 
	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_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_skbs(sq, true);

	free_old_xmit_skbs(sq, !!budget);



	if (sq->vq->num_free >= 2 + MAX_SKB_FRAGS)

		netif_tx_wake_queue(txq);