diff mbox series

[bpf,1/3] bpf, sockmap: Fix update element with same

Message ID 20241202-sockmap-replace-v1-1-1e88579e7bd5@rbox.co (mailing list archive)
State New
Headers show
Series bpf, sockmap: Fix the element replace | expand

Commit Message

Michal Luczaj Dec. 2, 2024, 11:29 a.m. UTC 
Consider a sockmap entry being updated with the same socket:

	osk = stab->sks[idx];
	sock_map_add_link(psock, link, map, &stab->sks[idx]);
	stab->sks[idx] = sk;
	if (osk)
		sock_map_unref(osk, &stab->sks[idx]);

Due to sock_map_unref(), which invokes sock_map_del_link(), all the psock's
links for stab->sks[idx] are torn:

	list_for_each_entry_safe(link, tmp, &psock->link, list) {
		if (link->link_raw == link_raw) {
			...
			list_del(&link->list);
			sk_psock_free_link(link);
		}
	}

And that includes the new link sock_map_add_link() added just before the
unref.

This results in a sockmap holding a socket, but without the respective
link. This in turn means that close(sock) won't trigger the cleanup, i.e. a
closed socket will not be automatically removed from the sockmap.

Stop tearing the links when a matching link_raw is found.

Signed-off-by: Michal Luczaj <mhal@rbox.co>
---
 net/core/sock_map.c | 1 +
 1 file changed, 1 insertion(+)
diff mbox series

Patch

diff --git a/net/core/sock_map.c b/net/core/sock_map.c
index 78347d7d25ef31525f8ec0a755a18e5793ad92c0..20b348b1964a10a1b0bfbe1a90a4a4cd99715b81 100644
--- a/net/core/sock_map.c
+++ b/net/core/sock_map.c
@@ -159,6 +159,7 @@  static void sock_map_del_link(struct sock *sk,
 				verdict_stop = true;
 			list_del(&link->list);
 			sk_psock_free_link(link);
+			break;
 		}
 	}
 	spin_unlock_bh(&psock->link_lock);