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From: "Maciej Żenczykowski" <zenczykowski@gmail.com>
To: "Maciej Żenczykowski" <maze@google.com>
Cc: Linux USB Mailing List <linux-usb@vger.kernel.org>,
	Brooke Basile <brookebasile@gmail.com>,
	"Bryan O'Donoghue" <bryan.odonoghue@linaro.org>,
	Felipe Balbi <balbi@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Lorenzo Colitti <lorenzo@google.com>
Subject: [PATCH 3/6] usb: gadget: f_ncm: remove check for NULL skb_tx_data in timer function
Date: Thu,  1 Jul 2021 04:48:31 -0700	[thread overview]
Message-ID: <20210701114834.884597-3-zenczykowski@gmail.com> (raw)
In-Reply-To: <20210701114834.884597-1-zenczykowski@gmail.com>

From: Maciej Żenczykowski <maze@google.com>

This condition is already checked for in ncm_wrap_ntb(),
except that that check is done with eth_dev->lock held
(it is grabbed by eth_start_xmit).

It's best to not be reaching into ncm struct without locks held.

Cc: Brooke Basile <brookebasile@gmail.com>
Cc: "Bryan O'Donoghue" <bryan.odonoghue@linaro.org>
Cc: Felipe Balbi <balbi@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Lorenzo Colitti <lorenzo@google.com>
Signed-off-by: Maciej Żenczykowski <maze@google.com>
---
 drivers/usb/gadget/function/f_ncm.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/usb/gadget/function/f_ncm.c b/drivers/usb/gadget/function/f_ncm.c
index e45a938424a4..77f55b3c805a 100644
--- a/drivers/usb/gadget/function/f_ncm.c
+++ b/drivers/usb/gadget/function/f_ncm.c
@@ -1156,8 +1156,7 @@ static enum hrtimer_restart ncm_tx_timeout(struct hrtimer *data)
 	struct f_ncm *ncm = container_of(data, struct f_ncm, task_timer);
 	struct net_device *netdev = READ_ONCE(ncm->netdev);
 
-	/* Only send if data is available. */
-	if (netdev && ncm->skb_tx_data) {
+	if (netdev) {
 		/* XXX This allowance of a NULL skb argument to ndo_start_xmit
 		 * XXX is not sane.  The gadget layer should be redesigned so
 		 * XXX that the dev->wrap() invocations to build SKBs is transparent
-- 
2.32.0.93.g670b81a890-goog


  parent reply	other threads:[~2021-07-01 11:48 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-01 11:48 [PATCH 1/6] usb: gadget: f_ncm: remove timer_force_tx field Maciej Żenczykowski
2021-07-01 11:48 ` [PATCH 2/6] usb: gadget: f_ncm: remove spurious boolean timer_stopping Maciej Żenczykowski
2021-07-01 11:48 ` Maciej Żenczykowski [this message]
2021-07-01 11:48 ` [PATCH 4/6] usb: gadget: f_ncm: remove spurious if statement Maciej Żenczykowski
2021-07-01 11:48 ` [PATCH 5/6] usb: gadget: f_ncm: ncm_wrap_ntb - move var definitions into " Maciej Żenczykowski
2021-07-01 11:48 ` [PATCH 6/6] usb: gadget: u_ether: fix a potential null pointer dereference Maciej Żenczykowski

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