net: annotate a data-race in __dev_xmit_skb()

q->limit is read locklessly, add a READ_ONCE().

Fixes: 100dfa74cad9 ("net: dev_queue_xmit() llist adoption")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20251121083256.674562-12-edumazet@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/net/core/dev.c b/net/core/dev.c
index 53e2496dc4292284072946fd9131d3f9a0c0af44..10042139dbb054b9a93dfb019477a80263feb029 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4194,7 +4194,7 @@ no_lock_out:
        do {
                if (first_n && !defer_count) {
                        defer_count = atomic_long_inc_return(&q->defer_count);
-                       if (unlikely(defer_count > q->limit)) {
+                       if (unlikely(defer_count > READ_ONCE(q->limit))) {
                                kfree_skb_reason(skb, SKB_DROP_REASON_QDISC_DROP);
                                return NET_XMIT_DROP;
                        }