diff options
| author | Jinliang Wang <jinliangw@google.com> | 2025-10-26 23:55:30 -0700 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2025-10-29 17:55:14 -0700 |
| commit | da2522df3fcc6f57068470cbdcd6516d9eb76b37 (patch) | |
| tree | 5485c4c38de982255fdb272476205d10ea87ada7 /drivers | |
| parent | 53110232c95ff56067fd96c75a1a1c53d10dcd98 (diff) | |
net: mctp: Fix tx queue stall
The tx queue can become permanently stuck in a stopped state due to a
race condition between the URB submission path and its completion
callback.
The URB completion callback can run immediately after usb_submit_urb()
returns, before the submitting function calls netif_stop_queue(). If
this occurs, the queue state management becomes desynchronized, leading
to a stall where the queue is never woken.
Fix this by moving the netif_stop_queue() call to before submitting the
URB. This closes the race window by ensuring the network stack is aware
the queue is stopped before the URB completion can possibly run.
Fixes: 0791c0327a6e ("net: mctp: Add MCTP USB transport driver")
Signed-off-by: Jinliang Wang <jinliangw@google.com>
Acked-by: Jeremy Kerr <jk@codeconstruct.com.au>
Link: https://patch.msgid.link/20251027065530.2045724-1-jinliangw@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/net/mctp/mctp-usb.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/drivers/net/mctp/mctp-usb.c b/drivers/net/mctp/mctp-usb.c index 36ccc53b1797..ef860cfc629f 100644 --- a/drivers/net/mctp/mctp-usb.c +++ b/drivers/net/mctp/mctp-usb.c @@ -96,11 +96,13 @@ static netdev_tx_t mctp_usb_start_xmit(struct sk_buff *skb, skb->data, skb->len, mctp_usb_out_complete, skb); + /* Stops TX queue first to prevent race condition with URB complete */ + netif_stop_queue(dev); rc = usb_submit_urb(urb, GFP_ATOMIC); - if (rc) + if (rc) { + netif_wake_queue(dev); goto err_drop; - else - netif_stop_queue(dev); + } return NETDEV_TX_OK; |