2017-08-18 11:11:58

by Colin King

Subject: [PATCH] nfp: fix infinite loop on umapping cleanup

From: Colin Ian King <[email protected]>

The while loop that performs the dma page unmapping never decrements
index counter f and hence loops forever. Fix this with a pre-decrement
on f.

Detected by CoverityScan, CID#1357309 ("Infinite loop")

Fixes: 4c3523623dc0 ("net: add driver for Netronome NFP4000/NFP6000 NIC VFs")
Signed-off-by: Colin Ian King <[email protected]>
---
drivers/net/ethernet/netronome/nfp/nfp_net_common.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/netronome/nfp/nfp_net_common.c b/drivers/net/ethernet/netronome/nfp/nfp_net_common.c
index 4a990033c4d5..732f1d315fba 100644
--- a/drivers/net/ethernet/netronome/nfp/nfp_net_common.c
+++ b/drivers/net/ethernet/netronome/nfp/nfp_net_common.c
@@ -908,8 +908,7 @@ static int nfp_net_tx(struct sk_buff *skb, struct net_device *netdev)
return NETDEV_TX_OK;

err_unmap:
- --f;
- while (f >= 0) {
+ while (--f >= 0) {
frag = &skb_shinfo(skb)->frags[f];
dma_unmap_page(dp->dev, tx_ring->txbufs[wr_idx].dma_addr,
skb_frag_size(frag), DMA_TO_DEVICE);
--
2.11.0

2017-08-18 14:32:39

by Jakub Kicinski

Subject: Re: [oss-drivers] [PATCH] nfp: fix infinite loop on umapping cleanup

On Fri, 18 Aug 2017 12:11:50 +0100, Colin King wrote:
> From: Colin Ian King <[email protected]>
>
> The while loop that performs the dma page unmapping never decrements
> index counter f and hence loops forever. Fix this with a pre-decrement
> on f.
>
> Detected by CoverityScan, CID#1357309 ("Infinite loop")
>
> Fixes: 4c3523623dc0 ("net: add driver for Netronome NFP4000/NFP6000 NIC VFs")
> Signed-off-by: Colin Ian King <[email protected]>

Acked-by: Jakub Kicinski <[email protected]>

Thanks!

2017-08-18 17:29:21

by David Miller

Subject: Re: [PATCH] nfp: fix infinite loop on umapping cleanup

From: Colin King <[email protected]>
Date: Fri, 18 Aug 2017 12:11:50 +0100

> From: Colin Ian King <[email protected]>
>
> The while loop that performs the dma page unmapping never decrements
> index counter f and hence loops forever. Fix this with a pre-decrement
> on f.
>
> Detected by CoverityScan, CID#1357309 ("Infinite loop")
>
> Fixes: 4c3523623dc0 ("net: add driver for Netronome NFP4000/NFP6000 NIC VFs")
> Signed-off-by: Colin Ian King <[email protected]>

Applied and queued up for -stable.