From 51de3600093429e3b712e5f091d767babc5dd6df Mon Sep 17 00:00:00 2001 From: Ying Lu Date: Wed, 2 Apr 2025 16:58:59 +0800 Subject: [PATCH] usbnet:fix NPE during rx_complete MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Link: https://patch.msgid.link/4c9ef2efaa07eb7f9a5042b74348a67e5a3a7aea.1743584159.git.luying1@xiaomi.com Signed-off-by: Jakub Kicinski --- drivers/net/usb/usbnet.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c index aeab2308b150..724b93aa4f7e 100644 --- a/drivers/net/usb/usbnet.c +++ b/drivers/net/usb/usbnet.c @@ -530,7 +530,8 @@ static int rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags) 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); @@ -551,8 +552,7 @@ static int rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags) 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");