From 0a196d561227353bead35e469fdf8ca8cd0426e2 Mon Sep 17 00:00:00 2001 From: Foster Snowhill Date: Tue, 6 Aug 2024 19:28:07 +0200 Subject: [PATCH] usbnet: ipheth: drop RX URBs with no payload BugLink: https://bugs.launchpad.net/bugs/2086138 [ Upstream commit 94d7eeb6c0ef0310992944f0d0296929816a2cb0 ] On iPhone 15 Pro Max one can observe periodic URBs with no payload on the "bulk in" (RX) endpoint. These don't seem to do anything meaningful. Reproduced on iOS 17.5.1 and 17.6. This behaviour isn't observed on iPhone 11 on the same iOS version. The nature of these zero-length URBs is so far unknown. Drop RX URBs with no payload. Signed-off-by: Foster Snowhill Signed-off-by: David S. Miller Signed-off-by: Sasha Levin Signed-off-by: Koichiro Den Signed-off-by: Roxana Nicolescu --- drivers/net/usb/ipheth.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/net/usb/ipheth.c b/drivers/net/usb/ipheth.c index 017255615508..f04c7bf79665 100644 --- a/drivers/net/usb/ipheth.c +++ b/drivers/net/usb/ipheth.c @@ -286,6 +286,12 @@ static void ipheth_rcvbulk_callback(struct urb *urb) return; } + /* iPhone may periodically send URBs with no payload + * on the "bulk in" endpoint. It is safe to ignore them. + */ + if (urb->actual_length == 0) + goto rx_submit; + /* RX URBs starting with 0x00 0x01 do not encapsulate Ethernet frames, * but rather are control frames. Their purpose is not documented, and * they don't affect driver functionality, okay to drop them.