[PATCH net] liquidio: read sc->iq_no before release sc

[PATCH net] liquidio: read sc->iq_no before release sc

[Pan Bian]

The function lio_vf_rep_packet_sent_callback releases the occupation of
sc via octeon_free_soft_command. sc should not be used after that.
Unfortunately, sc->iq_no is read. To fix this, the patch stores sc->iq_no
into a local variable before releasing sc and then uses the local variable
instead of sc->iq_no.

Signed-off-by: Pan Bian <bianpan2016@163.com>
---
 drivers/net/ethernet/cavium/liquidio/lio_vf_rep.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/cavium/liquidio/lio_vf_rep.c b/drivers/net/ethernet/cavium/liquidio/lio_vf_rep.c
index ea9859e..de61060 100644
--- a/drivers/net/ethernet/cavium/liquidio/lio_vf_rep.c
+++ b/drivers/net/ethernet/cavium/liquidio/lio_vf_rep.c
@@ -349,13 +349,15 @@ lio_vf_rep_packet_sent_callback(struct octeon_device *oct,
 	struct octeon_soft_command *sc = (struct octeon_soft_command *)buf;
 	struct sk_buff *skb = sc->ctxptr;
 	struct net_device *ndev = skb->dev;
+	u32 iq_no;
 
 	dma_unmap_single(&oct->pci_dev->dev, sc->dmadptr,
 			 sc->datasize, DMA_TO_DEVICE);
 	dev_kfree_skb_any(skb);
+	iq_no = sc->iq_no;
 	octeon_free_soft_command(oct, sc);
 
-	if (octnet_iq_is_full(oct, sc->iq_no))
+	if (octnet_iq_is_full(oct, iq_no))
 		return;
 
 	if (netif_queue_stopped(ndev))
-- 
2.7.4

Re: [PATCH net] liquidio: read sc->iq_no before release sc

[David Miller]

From: Pan Bian <bianpan2016@163.com>
Date: Thu, 29 Nov 2018 07:54:22 +0800

> The function lio_vf_rep_packet_sent_callback releases the occupation of
> sc via octeon_free_soft_command. sc should not be used after that.
> Unfortunately, sc->iq_no is read. To fix this, the patch stores sc->iq_no
> into a local variable before releasing sc and then uses the local variable
> instead of sc->iq_no.
> 
> Signed-off-by: Pan Bian <bianpan2016@163.com>

Applied.