Thread (25 messages) 25 messages, 3 authors, 2020-06-02

Re: [PATCH bpf-next v2 05/12] bpf, cgroup: Return ENOLINK for auto-detached links on update

From: Andrii Nakryiko <hidden>
Date: 2020-06-01 22:31:18
Also in: bpf

On Sun, May 31, 2020 at 1:29 AM Jakub Sitnicki [off-list ref] wrote:
Failure to update a bpf_link because it has been auto-detached by a dying
cgroup currently results in EINVAL error, even though the arguments passed
to bpf() syscall are not wrong.

bpf_links attaching to netns in this case will return ENOLINK, which
carries the message that the link is no longer attached to anything.

Change cgroup bpf_links to do the same to keep the uAPI errors consistent.

Fixes: 0c991ebc8c69 ("bpf: Implement bpf_prog replacement for an active bpf_cgroup_link")
Suggested-by: Lorenz Bauer <redacted>
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
---
Looks good, thanks!

Acked-by: Andrii Nakryiko <redacted>
quoted hunk ↗ jump to hunk
 kernel/bpf/cgroup.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
index 5c0e964105ac..fdf7836750a3 100644
--- a/kernel/bpf/cgroup.c
+++ b/kernel/bpf/cgroup.c
@@ -595,7 +595,7 @@ static int cgroup_bpf_replace(struct bpf_link *link, struct bpf_prog *new_prog,
        mutex_lock(&cgroup_mutex);
        /* link might have been auto-released by dying cgroup, so fail */
        if (!cg_link->cgroup) {
-               ret = -EINVAL;
+               ret = -ENOLINK;
                goto out_unlock;
        }
        if (old_prog && link->prog != old_prog) {
--
2.25.4
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