netdev - [PATCH v2] can: j1939: transport: replace kfree_skb() with dev_kfree_skb

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Date:   Thu, 27 Oct 2022 17:12:37 +0800
From:   Yang Yingliang <yangyingliang@...wei.com>
To:     <linux-can@...r.kernel.org>, <netdev@...r.kernel.org>
CC:     <robin@...tonic.nl>, <linux@...pel-privat.de>,
        <kernel@...gutronix.de>, <socketcan@...tkopp.net>,
        <mkl@...gutronix.de>
Subject: [PATCH v2] can: j1939: transport: replace kfree_skb() with dev_kfree_skb_irq()

It is not allowed to call kfree_skb() from hardware interrupt
context or with interrupts being disabled. The skb is unlinked
from the queue, so it can be freed after spin_unlock_irqrestore().

Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol")
Signed-off-by: Yang Yingliang <yangyingliang@...wei.com>
---
v1 -> v2:
  Move kfree_skb() after spin_unlock_irqrestore().
---
 net/can/j1939/transport.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/can/j1939/transport.c b/net/can/j1939/transport.c
index d7d86c944d76..55f29c9f9e08 100644
--- a/net/can/j1939/transport.c
+++ b/net/can/j1939/transport.c
@@ -342,10 +342,12 @@ static void j1939_session_skb_drop_old(struct j1939_session *session)
 		__skb_unlink(do_skb, &session->skb_queue);
 		/* drop ref taken in j1939_session_skb_queue() */
 		skb_unref(do_skb);
+		spin_unlock_irqrestore(&session->skb_queue.lock, flags);
 
 		kfree_skb(do_skb);
+	} else {
+		spin_unlock_irqrestore(&session->skb_queue.lock, flags);
 	}
-	spin_unlock_irqrestore(&session->skb_queue.lock, flags);
 }
 
 void j1939_session_skb_queue(struct j1939_session *session,
-- 
2.25.1