[PATCH 4.4 039/101] net: korina: Fix NAPI versus resources freeing

Greg Kroah-Hartman
2017-07-03T13:38:18Z

From: Florian Fainelli <f.fainelli@gmail.com>

commit e6afb1ad88feddf2347ea779cfaf4d03d3cd40b6 upstream.

Commit beb0babfb77e ("korina: disable napi on close and restart")
introduced calls to napi_disable() that were missing before,
unfortunately this leaves a small window during which NAPI has a chance
to run, yet we just freed resources since korina_free_ring() has been
called:

Fix this by disabling NAPI first then freeing resource, and make sure
that we also cancel the restart task before doing the resource freeing.

Fixes: beb0babfb77e ("korina: disable napi on close and restart")
Reported-by: Alexandros C. Couloumbis <alex@ozo.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/net/ethernet/korina.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

--- a/drivers/net/ethernet/korina.c
+++ b/drivers/net/ethernet/korina.c
@@ -900,10 +900,10 @@ static void korina_restart_task(struct w
DMA_STAT_DONE | DMA_STAT_HALT | DMA_STAT_ERR,
&lp->rx_dma_regs->dmasm);

- korina_free_ring(dev);
-
napi_disable(&lp->napi);

+ korina_free_ring(dev);
+
if (korina_init(dev) < 0) {
printk(KERN_ERR "%s: cannot restart device\n", dev->name);
return;
@@ -1064,12 +1064,12 @@ static int korina_close(struct net_devic
tmp = tmp | DMA_STAT_DONE | DMA_STAT_HALT | DMA_STAT_ERR;
writel(tmp, &lp->rx_dma_regs->dmasm);

- korina_free_ring(dev);
-
napi_disable(&lp->napi);

cancel_work_sync(&lp->restart_task);

+ korina_free_ring(dev);
+
free_irq(lp->rx_irq, dev);
free_irq(lp->tx_irq, dev);
free_irq(lp->ovr_irq, dev);