When we fail to allocate a frag skb, we need put the refcnt of the page and drop
the rest of the buffers. Otherwise the page was leaked and driver won't get a
correct head buffer after this failure.
This bug was introduced by commit 2613af0ed18a11d5c566a81f9a6510b73180660a
(virtio_net: migrate mergeable rx buffers to page frag allocators).
Cc: Rusty Russell <ru...@rustcorp.com.au>
Cc: Michael S. Tsirkin <m...@redhat.com>
Cc: Michael Dalton <mwdal...@google.com>
Cc: Eric Dumazet <eduma...@google.com>
Signed-off-by: Jason Wang <jasow...@redhat.com>
---
The patch was needed for 3.12 stable.
---
drivers/net/virtio_net.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index de1d6ca..f6f1e20 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -339,9 +339,12 @@ static int receive_mergeable(struct receive_queue *rq,
struct sk_buff *head_skb)
head_skb->dev->name);
len = MERGE_BUFFER_LEN;
}
+ page = virt_to_head_page(buf);
if (unlikely(num_skb_frags == MAX_SKB_FRAGS)) {
struct sk_buff *nskb = alloc_skb(0, GFP_ATOMIC);
if (unlikely(!nskb)) {
+ put_page(page);
+ drop_mergeable_buffer(rq, num_buf);
head_skb->dev->stats.rx_dropped++;
return -ENOMEM;
}
@@ -358,7 +361,6 @@ static int receive_mergeable(struct receive_queue *rq,
struct sk_buff *head_skb)
head_skb->len += len;
head_skb->truesize += MERGE_BUFFER_LEN;
}
- page = virt_to_head_page(buf);
offset = buf - (char *)page_address(page);
if (skb_can_coalesce(curr_skb, num_skb_frags, page, offset)) {
put_page(page);
--
1.8.3.2
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