diff options
| -rw-r--r-- | kernel/bpf/bpf_iter.c | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/kernel/bpf/bpf_iter.c b/kernel/bpf/bpf_iter.c index 03f5832909db..0542a243b78c 100644 --- a/kernel/bpf/bpf_iter.c +++ b/kernel/bpf/bpf_iter.c @@ -23,6 +23,9 @@ struct bpf_iter_link { static struct list_head targets = LIST_HEAD_INIT(targets); static DEFINE_MUTEX(targets_mutex); +/* protect bpf_iter_link changes */ +static DEFINE_MUTEX(link_mutex); + int bpf_iter_reg_target(struct bpf_iter_reg *reg_info) { struct bpf_iter_target_info *tinfo; @@ -111,9 +114,37 @@ static void bpf_iter_link_dealloc(struct bpf_link *link) kfree(iter_link); } +static int bpf_iter_link_replace(struct bpf_link *link, + struct bpf_prog *new_prog, + struct bpf_prog *old_prog) +{ + int ret = 0; + + mutex_lock(&link_mutex); + if (old_prog && link->prog != old_prog) { + ret = -EPERM; + goto out_unlock; + } + + if (link->prog->type != new_prog->type || + link->prog->expected_attach_type != new_prog->expected_attach_type || + link->prog->aux->attach_btf_id != new_prog->aux->attach_btf_id) { + ret = -EINVAL; + goto out_unlock; + } + + old_prog = xchg(&link->prog, new_prog); + bpf_prog_put(old_prog); + +out_unlock: + mutex_unlock(&link_mutex); + return ret; +} + static const struct bpf_link_ops bpf_iter_link_lops = { .release = bpf_iter_link_release, .dealloc = bpf_iter_link_dealloc, + .update_prog = bpf_iter_link_replace, }; int bpf_iter_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) |