5.15-stable review patch. If anyone has any objections, please let me know.
------------------
From: Koichiro Den <redacted>
commit 873ce713fef5dde0939220f04f3484ec86a16fba upstream.
Commit f195a1a6fe41 ("ntb: Drop packets when qp link is down") meant to
make ntb_transport_tx_enqueue() drop packets submitted while the QP link
is down, but it only returns 0 without consuming the packet. Zero means
success by this function's contract, so ntb_netdev reports NETDEV_TX_OK
and forgets the skb: nothing queued it, nothing frees it, and it leaks,
one skb for every transmit racing a link-down.
Return -ENOLINK instead, restoring the contract that a non-zero return
leaves the buffer owned by the caller. With the preceding patch,
ntb_netdev frees the skb on non-retryable enqueue failures and returns
NETDEV_TX_OK, so a packet racing with link-down is dropped without leaking
or entering a busy retry loop.
Fixes: f195a1a6fe41 ("ntb: Drop packets when qp link is down")
Cc: <redacted>
Signed-off-by: Koichiro Den <redacted>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Link: https://patch.msgid.link/20260817053519.4135287-4-den@valinux.co.jp (local)
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/ntb/ntb_transport.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
--- a/drivers/ntb/ntb_transport.c
+++ b/drivers/ntb/ntb_transport.c
@@ -2291,9 +2291,8 @@ int ntb_transport_tx_enqueue(struct ntb_
if (!qp || !len)
return -EINVAL;
- /* If the qp link is down already, just ignore. */
if (!qp->link_is_up)
- return 0;
+ return -ENOLINK;
entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q);
if (!entry) {