On 12/9/24 06:47, John Fastabend wrote:
Michal Luczaj wrote:
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
Thanks. LGTM.
Reviewed-by: John Fastabend john.fastabend@gmail.com
Thanks, and sorry for a missing tag:
Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface")