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author | Linus Torvalds <torvalds@linux-foundation.org> | 2024-01-22 09:40:05 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2024-01-22 09:40:05 -0800 |
commit | 0f0d819aef6feb711dfd773ef906b9cbd02a2419 (patch) | |
tree | d6b8e0ae4dcd3acf1a3b6da067a94c3b04c1307e | |
parent | 6613476e225e090cc9aad49be7fa504e290dd33d (diff) | |
parent | c7ec4f2d684e17d69bbdd7c4324db0ef5daac26a (diff) | |
download | linux-bcache-0f0d819aef6feb711dfd773ef906b9cbd02a2419.tar.gz |
Merge tag 'xsa448-6.8-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen netback fix from Juergen Gross:
"Transmit requests in Xen's virtual network protocol can consist of
multiple parts. While not really useful, except for the initial part
any of them may be of zero length, i.e. carry no data at all.
Besides a certain initial portion of the to be transferred data, these
parts are directly translated into what Linux calls SKB fragments.
Such converted request parts can, when for a particular SKB they are
all of length zero, lead to a de-reference of NULL in core networking
code"
* tag 'xsa448-6.8-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
xen-netback: don't produce zero-size SKB frags
-rw-r--r-- | drivers/net/xen-netback/netback.c | 44 |
1 files changed, 38 insertions, 6 deletions
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c index 88f760a7cbc354..d7503aef599f04 100644 --- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c @@ -463,12 +463,25 @@ static void xenvif_get_requests(struct xenvif_queue *queue, } for (shinfo->nr_frags = 0; nr_slots > 0 && shinfo->nr_frags < MAX_SKB_FRAGS; - shinfo->nr_frags++, gop++, nr_slots--) { + nr_slots--) { + if (unlikely(!txp->size)) { + unsigned long flags; + + spin_lock_irqsave(&queue->response_lock, flags); + make_tx_response(queue, txp, 0, XEN_NETIF_RSP_OKAY); + push_tx_responses(queue); + spin_unlock_irqrestore(&queue->response_lock, flags); + ++txp; + continue; + } + index = pending_index(queue->pending_cons++); pending_idx = queue->pending_ring[index]; xenvif_tx_create_map_op(queue, pending_idx, txp, txp == first ? extra_count : 0, gop); frag_set_pending_idx(&frags[shinfo->nr_frags], pending_idx); + ++shinfo->nr_frags; + ++gop; if (txp == first) txp = txfrags; @@ -481,20 +494,39 @@ static void xenvif_get_requests(struct xenvif_queue *queue, shinfo = skb_shinfo(nskb); frags = shinfo->frags; - for (shinfo->nr_frags = 0; shinfo->nr_frags < nr_slots; - shinfo->nr_frags++, txp++, gop++) { + for (shinfo->nr_frags = 0; shinfo->nr_frags < nr_slots; ++txp) { + if (unlikely(!txp->size)) { + unsigned long flags; + + spin_lock_irqsave(&queue->response_lock, flags); + make_tx_response(queue, txp, 0, + XEN_NETIF_RSP_OKAY); + push_tx_responses(queue); + spin_unlock_irqrestore(&queue->response_lock, + flags); + continue; + } + index = pending_index(queue->pending_cons++); pending_idx = queue->pending_ring[index]; xenvif_tx_create_map_op(queue, pending_idx, txp, 0, gop); frag_set_pending_idx(&frags[shinfo->nr_frags], pending_idx); + ++shinfo->nr_frags; + ++gop; } - skb_shinfo(skb)->frag_list = nskb; - } else if (nskb) { + if (shinfo->nr_frags) { + skb_shinfo(skb)->frag_list = nskb; + nskb = NULL; + } + } + + if (nskb) { /* A frag_list skb was allocated but it is no longer needed - * because enough slots were converted to copy ops above. + * because enough slots were converted to copy ops above or some + * were empty. */ kfree_skb(nskb); } |