From b3b952168ee1f220ba729fa100fd9d5aa752eb03 Mon Sep 17 00:00:00 2001 From: =?utf8?q?=C3=8D=C3=B1igo=20Huguet?= Date: Wed, 14 Sep 2022 13:11:35 +0200 Subject: [PATCH] sfc: fix null pointer dereference in efx_hard_start_xmit MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit [ Upstream commit 0a242eb2913a4aa3d6fbdb86559f27628e9466f3 ] Trying to get the channel from the tx_queue variable here is wrong because we can only be here if tx_queue is NULL, so we shouldn't dereference it. As the above comment in the code says, this is very unlikely to happen, but it's wrong anyway so let's fix it. I hit this issue because of a different bug that caused tx_queue to be NULL. If that happens, this is the error message that we get here: BUG: unable to handle kernel NULL pointer dereference at 0000000000000020 [...] RIP: 0010:efx_hard_start_xmit+0x153/0x170 [sfc] Fixes: 12804793b17c ("sfc: decouple TXQ type from label") Reported-by: Tianhao Zhao Signed-off-by: Íñigo Huguet Acked-by: Edward Cree Link: https://lore.kernel.org/r/20220914111135.21038-1-ihuguet@redhat.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- drivers/net/ethernet/sfc/tx.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/ethernet/sfc/tx.c b/drivers/net/ethernet/sfc/tx.c index 138bca611341..80ed7f760bd3 100644 --- a/drivers/net/ethernet/sfc/tx.c +++ b/drivers/net/ethernet/sfc/tx.c @@ -549,7 +549,7 @@ netdev_tx_t efx_hard_start_xmit(struct sk_buff *skb, * previous packets out. */ if (!netdev_xmit_more()) - efx_tx_send_pending(tx_queue->channel); + efx_tx_send_pending(efx_get_tx_channel(efx, index)); return NETDEV_TX_OK; } -- 2.44.0