6.6-stable review patch. If anyone has any objections, please let me know.
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From: Anssi Hannula anssi.hannula@bitwise.fi
[ Upstream commit ef79f00be72bd81d2e1e6f060d83cf7e425deee4 ]
can_put_echo_skb() takes ownership of the SKB and it may be freed during or after the call.
However, xilinx_can xcan_write_frame() keeps using SKB after the call.
Fix that by only calling can_put_echo_skb() after the code is done touching the SKB.
The tx_lock is held for the entire xcan_write_frame() execution and also on the can_get_echo_skb() side so the order of operations does not matter.
An earlier fix commit 3d3c817c3a40 ("can: xilinx_can: Fix usage of skb memory") did not move the can_put_echo_skb() call far enough.
Signed-off-by: Anssi Hannula anssi.hannula@bitwise.fi Fixes: 1598efe57b3e ("can: xilinx_can: refactor code in preparation for CAN FD support") Link: https://patch.msgid.link/20250822095002.168389-1-anssi.hannula@bitwise.fi [mkl: add "commit" in front of sha1 in patch description] [mkl: fix indention] Signed-off-by: Marc Kleine-Budde mkl@pengutronix.de Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/can/xilinx_can.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-)
diff --git a/drivers/net/can/xilinx_can.c b/drivers/net/can/xilinx_can.c index abe58f1030433..57d1209134f11 100644 --- a/drivers/net/can/xilinx_can.c +++ b/drivers/net/can/xilinx_can.c @@ -628,14 +628,6 @@ static void xcan_write_frame(struct net_device *ndev, struct sk_buff *skb, dlc |= XCAN_DLCR_EDL_MASK; }
- if (!(priv->devtype.flags & XCAN_FLAG_TX_MAILBOXES) && - (priv->devtype.flags & XCAN_FLAG_TXFEMP)) - can_put_echo_skb(skb, ndev, priv->tx_head % priv->tx_max, 0); - else - can_put_echo_skb(skb, ndev, 0, 0); - - priv->tx_head++; - priv->write_reg(priv, XCAN_FRAME_ID_OFFSET(frame_offset), id); /* If the CAN frame is RTR frame this write triggers transmission * (not on CAN FD) @@ -668,6 +660,14 @@ static void xcan_write_frame(struct net_device *ndev, struct sk_buff *skb, data[1]); } } + + if (!(priv->devtype.flags & XCAN_FLAG_TX_MAILBOXES) && + (priv->devtype.flags & XCAN_FLAG_TXFEMP)) + can_put_echo_skb(skb, ndev, priv->tx_head % priv->tx_max, 0); + else + can_put_echo_skb(skb, ndev, 0, 0); + + priv->tx_head++; }
/**