tipc: fix memory leak in tipc_link_xmit

In case the backlog transmit queue for system-importance messages is overloaded,
tipc_link_xmit() returns -ENOBUFS but the skb list is not purged. This leads to
memory leak and failure when a skb is allocated.

This commit fixes this issue by purging the skb list before tipc_link_xmit()
returns.

Fixes: 365ad353c256 ("tipc: reduce risk of user starvation during link congestion")
Signed-off-by: Tung Nguyen <tung.quang.nguyen@est.tech>
Link: https://patch.msgid.link/20250403092431.514063-1-tung.quang.nguyen@est.tech
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/net/tipc/link.c b/net/tipc/link.c
index 50c2e0846ea4df02a78a7be270463b20e3a79c86..18be6ff4c3db0ac80d5770032859244177ae12c7 100644 (file)
--- a/net/tipc/link.c
+++ b/net/tipc/link.c
@@ -1046,6 +1046,7 @@ int tipc_link_xmit(struct tipc_link *l, struct sk_buff_head *list,
        if (unlikely(l->backlog[imp].len >= l->backlog[imp].limit)) {
                if (imp == TIPC_SYSTEM_IMPORTANCE) {
                        pr_warn("%s<%s>, link overflow", link_rst_msg, l->name);
+                       __skb_queue_purge(list);
                        return -ENOBUFS;
                }
                rc = link_schedule_user(l, hdr);