| Message ID | 1482503852-12438-4-git-send-email-jasowang@redhat.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
On 16-12-23 06:37 AM, Jason Wang wrote: > We don't put page during linearizing, the would cause leaking when > xmit through XDP_TX or the packet exceeds PAGE_SIZE. Fix them by > put page accordingly. Also decrease the number of buffers during > linearizing to make sure caller can free buffers correctly when packet > exceeds PAGE_SIZE. With this patch, we won't get OOM after linearize > huge number of packets. > > Cc: John Fastabend <john.r.fastabend@intel.com> > Signed-off-by: Jason Wang <jasowang@redhat.com> > --- Thanks! looks good. By the way do you happen to have any actual configuration where this path is hit? I obviously didn't test this very long other than a quick test with my hacked vhost driver. Acked-by: John Fastabend <john.r.fastabend@intel.com>
On 2016年12月23日 23:54, John Fastabend wrote: > On 16-12-23 06:37 AM, Jason Wang wrote: >> We don't put page during linearizing, the would cause leaking when >> xmit through XDP_TX or the packet exceeds PAGE_SIZE. Fix them by >> put page accordingly. Also decrease the number of buffers during >> linearizing to make sure caller can free buffers correctly when packet >> exceeds PAGE_SIZE. With this patch, we won't get OOM after linearize >> huge number of packets. >> >> Cc: John Fastabend <john.r.fastabend@intel.com> >> Signed-off-by: Jason Wang <jasowang@redhat.com> >> --- > Thanks! looks good. By the way do you happen to have any actual > configuration where this path is hit? I obviously didn't test this > very long other than a quick test with my hacked vhost driver. > > Acked-by: John Fastabend <john.r.fastabend@intel.com> Yes, I have. Just increase the MTU above 1500 for both virtio and tap and produce some traffic with size which will lead underestimated of rxbuf. Thanks
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index fe4562d..58ad40e 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -483,7 +483,7 @@ static struct sk_buff *receive_big(struct net_device *dev, * anymore. */ static struct page *xdp_linearize_page(struct receive_queue *rq, - u16 num_buf, + u16 *num_buf, struct page *p, int offset, unsigned int *len) @@ -497,7 +497,7 @@ static struct page *xdp_linearize_page(struct receive_queue *rq, memcpy(page_address(page) + page_off, page_address(p) + offset, *len); page_off += *len; - while (--num_buf) { + while (--*num_buf) { unsigned int buflen; unsigned long ctx; void *buf; @@ -507,19 +507,22 @@ static struct page *xdp_linearize_page(struct receive_queue *rq, if (unlikely(!ctx)) goto err_buf; + buf = mergeable_ctx_to_buf_address(ctx); + p = virt_to_head_page(buf); + off = buf - page_address(p); + /* guard against a misconfigured or uncooperative backend that * is sending packet larger than the MTU. */ - if ((page_off + buflen) > PAGE_SIZE) + if ((page_off + buflen) > PAGE_SIZE) { + put_page(p); goto err_buf; - - buf = mergeable_ctx_to_buf_address(ctx); - p = virt_to_head_page(buf); - off = buf - page_address(p); + } memcpy(page_address(page) + page_off, page_address(p) + off, buflen); page_off += buflen; + put_page(p); } *len = page_off; @@ -555,7 +558,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, /* This happens when rx buffer size is underestimated */ if (unlikely(num_buf > 1)) { /* linearize data for XDP */ - xdp_page = xdp_linearize_page(rq, num_buf, + xdp_page = xdp_linearize_page(rq, &num_buf, page, offset, &len); if (!xdp_page) goto err_xdp;
We don't put page during linearizing, the would cause leaking when xmit through XDP_TX or the packet exceeds PAGE_SIZE. Fix them by put page accordingly. Also decrease the number of buffers during linearizing to make sure caller can free buffers correctly when packet exceeds PAGE_SIZE. With this patch, we won't get OOM after linearize huge number of packets. Cc: John Fastabend <john.r.fastabend@intel.com> Signed-off-by: Jason Wang <jasowang@redhat.com> --- drivers/net/virtio_net.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-)