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authorFlorian Fainelli <f.fainelli@gmail.com>2016-12-04 19:22:05 -0800
committerDavid S. Miller <davem@davemloft.net>2016-12-05 15:35:39 -0500
commitc823abac17926767fb50175e098f087a6ac684c3 (patch)
tree82887ccb88651b5a77598d26a65eb555ab21ae38 /drivers/net/ethernet/cirrus
parent34e0f2c2d82d7d939bfa249672311050b3b537f1 (diff)
net: ep93xx_eth: Do not crash unloading module
When we unload the ep93xx_eth, whether we have opened the network interface or not, we will either hit a kernel paging request error, or a simple NULL pointer de-reference because: - if ep93xx_open has been called, we have created a valid DMA mapping for ep->descs, when we call ep93xx_stop, we also call ep93xx_free_buffers, ep->descs now has a stale value - if ep93xx_open has not been called, we have a NULL pointer for ep->descs, so performing any operation against that address just won't work Fix this by adding a NULL pointer check for ep->descs which means that ep93xx_free_buffers() was able to successfully tear down the descriptors and free the DMA cookie as well. Fixes: 1d22e05df818 ("[PATCH] Cirrus Logic ep93xx ethernet driver") Signed-off-by: Florian Fainelli <f.fainelli@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/ethernet/cirrus')
-rw-r--r--drivers/net/ethernet/cirrus/ep93xx_eth.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/net/ethernet/cirrus/ep93xx_eth.c b/drivers/net/ethernet/cirrus/ep93xx_eth.c
index de9f7c97d916..9a161e981529 100644
--- a/drivers/net/ethernet/cirrus/ep93xx_eth.c
+++ b/drivers/net/ethernet/cirrus/ep93xx_eth.c
@@ -468,6 +468,9 @@ static void ep93xx_free_buffers(struct ep93xx_priv *ep)
struct device *dev = ep->dev->dev.parent;
int i;
+ if (!ep->descs)
+ return;
+
for (i = 0; i < RX_QUEUE_ENTRIES; i++) {
dma_addr_t d;
@@ -490,6 +493,7 @@ static void ep93xx_free_buffers(struct ep93xx_priv *ep)
dma_free_coherent(dev, sizeof(struct ep93xx_descs), ep->descs,
ep->descs_dma_addr);
+ ep->descs = NULL;
}
static int ep93xx_alloc_buffers(struct ep93xx_priv *ep)