From 6caf8a6d6586d44fd72f4aa1021d14aa82affafb Mon Sep 17 00:00:00 2001
From: Marc Kleine-Budde <mkl@pengutronix.de>
Date: Wed, 9 Oct 2019 15:48:48 +0200
Subject: [PATCH] can: rx-offload: can_rx_offload_queue_tail(): fix error handling, avoid skb mem leak
Git-commit: 6caf8a6d6586d44fd72f4aa1021d14aa82affafb
Patch-mainline: v5.4-rc7
References: git-fixes

If the rx-offload skb_queue is full can_rx_offload_queue_tail() will not
queue the skb and return with an error.

This patch frees the skb in case of a full queue, which brings
can_rx_offload_queue_tail() in line with the
can_rx_offload_queue_sorted() function, which has been adjusted in the
previous patch.

The return value is adjusted to -ENOBUFS to better reflect the actual
problem.

The device stats handling is left to the caller.

Fixes: d254586c3453 ("can: rx-offload: Add support for HW fifo based irq offloading")
Reported-by: Kurt Van Dijck <dev.kurt@vandijck-laurijssen.be>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/net/can/rx-offload.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/drivers/net/can/rx-offload.c
+++ b/drivers/net/can/rx-offload.c
@@ -260,8 +260,10 @@ EXPORT_SYMBOL_GPL(can_rx_offload_get_ech
 			      struct sk_buff *skb)
 {
 	if (skb_queue_len(&offload->skb_queue) >
-	    offload->skb_queue_len_max)
-		return -ENOMEM;
+	    offload->skb_queue_len_max) {
+		kfree_skb(skb);
+		return -ENOBUFS;
+	}
 
 	skb_queue_tail(&offload->skb_queue, skb);
 	can_rx_offload_schedule(offload);