5.15-stable review patch. If anyone has any objections, please let me know.
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From: Ying Lu luying1@xiaomi.com
commit 51de3600093429e3b712e5f091d767babc5dd6df upstream.
Missing usbnet_going_away Check in Critical Path. The usb_submit_urb function lacks a usbnet_going_away validation, whereas __usbnet_queue_skb includes this check.
This inconsistency creates a race condition where: A URB request may succeed, but the corresponding SKB data fails to be queued.
Subsequent processes: (e.g., rx_complete → defer_bh → __skb_unlink(skb, list)) attempt to access skb->next, triggering a NULL pointer dereference (Kernel Panic).
Fixes: 04e906839a05 ("usbnet: fix cyclical race on disconnect with work queue") Cc: stable@vger.kernel.org Signed-off-by: Ying Lu luying1@xiaomi.com Link: https://patch.msgid.link/4c9ef2efaa07eb7f9a5042b74348a67e5a3a7aea.1743584159... Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/usb/usbnet.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
--- a/drivers/net/usb/usbnet.c +++ b/drivers/net/usb/usbnet.c @@ -533,7 +533,8 @@ static int rx_submit (struct usbnet *dev netif_device_present (dev->net) && test_bit(EVENT_DEV_OPEN, &dev->flags) && !test_bit (EVENT_RX_HALT, &dev->flags) && - !test_bit (EVENT_DEV_ASLEEP, &dev->flags)) { + !test_bit (EVENT_DEV_ASLEEP, &dev->flags) && + !usbnet_going_away(dev)) { switch (retval = usb_submit_urb (urb, GFP_ATOMIC)) { case -EPIPE: usbnet_defer_kevent (dev, EVENT_RX_HALT); @@ -554,8 +555,7 @@ static int rx_submit (struct usbnet *dev tasklet_schedule (&dev->bh); break; case 0: - if (!usbnet_going_away(dev)) - __usbnet_queue_skb(&dev->rxq, skb, rx_start); + __usbnet_queue_skb(&dev->rxq, skb, rx_start); } } else { netif_dbg(dev, ifdown, dev->net, "rx: stopped\n");