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authorManfred Schlaegl <manfred.schlaegl@ginzinger.com>2018-12-19 19:39:58 +0100
committerChristoph Muellner <christoph.muellner@theobroma-systems.com>2019-04-30 20:02:05 +0200
commit2044b635ff7c76499ec061793a7b7bb8639705cb (patch)
tree3b6f0f3e525ce3814d81b90c80b4d317258dce86
parent090432a43f47b8dccd8977c5b425e858d37ba3fa (diff)
can: dev: __can_get_echo_skb(): fix bogous check for non-existing skb by removing it
This patch revert commit 7da11ba5c506 ("can: dev: __can_get_echo_skb(): print error message, if trying to echo non existing skb") After introduction of this change we encountered following new error message on various i.MX plattforms (flexcan): | flexcan 53fc8000.can can0: __can_get_echo_skb: BUG! Trying to echo non | existing skb: can_priv::echo_skb[0] The introduction of the message was a mistake because priv->echo_skb[idx] = NULL is a perfectly valid in following case: If CAN_RAW_LOOPBACK is disabled (setsockopt) in applications, the pkt_type of the tx skb's given to can_put_echo_skb is set to PACKET_LOOPBACK. In this case can_put_echo_skb will not set priv->echo_skb[idx]. It is therefore kept NULL. As additional argument for revert: The order of check and usage of idx was changed. idx is used to access an array element before checking it's boundaries. Signed-off-by: Manfred Schlaegl <manfred.schlaegl@ginzinger.com> Fixes: 7da11ba5c506 ("can: dev: __can_get_echo_skb(): print error message, if trying to echo non existing skb") Cc: linux-stable <stable@vger.kernel.org> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
-rw-r--r--drivers/net/can/dev.c27
1 files changed, 13 insertions, 14 deletions
diff --git a/drivers/net/can/dev.c b/drivers/net/can/dev.c
index 1dbee1cb3df9..8b7c6425b681 100644
--- a/drivers/net/can/dev.c
+++ b/drivers/net/can/dev.c
@@ -426,8 +426,6 @@ EXPORT_SYMBOL_GPL(can_put_echo_skb);
struct sk_buff *__can_get_echo_skb(struct net_device *dev, unsigned int idx, u8 *len_ptr)
{
struct can_priv *priv = netdev_priv(dev);
- struct sk_buff *skb = priv->echo_skb[idx];
- struct canfd_frame *cf;
if (idx >= priv->echo_skb_max) {
netdev_err(dev, "%s: BUG! Trying to access can_priv::echo_skb out of bounds (%u/max %u)\n",
@@ -435,20 +433,21 @@ struct sk_buff *__can_get_echo_skb(struct net_device *dev, unsigned int idx, u8
return NULL;
}
- if (!skb) {
- netdev_err(dev, "%s: BUG! Trying to echo non existing skb: can_priv::echo_skb[%u]\n",
- __func__, idx);
- return NULL;
- }
+ if (priv->echo_skb[idx]) {
+ /* Using "struct canfd_frame::len" for the frame
+ * length is supported on both CAN and CANFD frames.
+ */
+ struct sk_buff *skb = priv->echo_skb[idx];
+ struct canfd_frame *cf = (struct canfd_frame *)skb->data;
+ u8 len = cf->len;
+
+ *len_ptr = len;
+ priv->echo_skb[idx] = NULL;
- /* Using "struct canfd_frame::len" for the frame
- * length is supported on both CAN and CANFD frames.
- */
- cf = (struct canfd_frame *)skb->data;
- *len_ptr = cf->len;
- priv->echo_skb[idx] = NULL;
+ return skb;
+ }
- return skb;
+ return NULL;
}
/*