From: Amery Hung <ameryhung@gmail.com>
To: bpf@vger.kernel.org
Cc: netdev@vger.kernel.org, alexei.starovoitov@gmail.com,
andrii@kernel.org, daniel@iogearbox.net, eddyz87@gmail.com,
memxor@gmail.com, martin.lau@kernel.org, shakeel.butt@linux.dev,
roman.gushchin@linux.dev, kuniyu@google.com,
kerneljasonxing@gmail.com, ameryhung@gmail.com,
kernel-team@meta.com
Subject: [PATCH bpf-next v2 04/15] bpf: Remove unnecessary prog_list_prog() check
Date: Tue, 23 Jun 2026 10:49:52 -0700 [thread overview]
Message-ID: <20260623175006.3136053-5-ameryhung@gmail.com> (raw)
In-Reply-To: <20260623175006.3136053-1-ameryhung@gmail.com>
From: Martin KaFai Lau <martin.lau@kernel.org>
effective_prog_pos(), called from replace_effective_prog() and
purge_effective_progs(), tests "!prog_list_prog(pl)" to skip a
'detaching' pl.
When detaching a pl, pl->prog and pl->link are set to NULL in case
the update_effective_progs() failed.
However, replace_effective_prog() is not detaching a pl,
so the case "!prog_list_prog()" will not happen.
In purge_effective_prog(), the pl->prog and pl->link are restored
before calling purge_effective_progs(), so the case "!prog_list_prog()"
will not happen either.
This patch removes them as a prep work for the upcoming work
in attaching struct_ops to cgroup. When attaching a struct_ops
to cgroup, there is a link->map case and the prog_list_prog()
will not consider the link->map. The replace_effective_prog()
and purge_effective_progs() will then incorrectly skip a pl
with struct_ops map attached to it.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Amery Hung <ameryhung@gmail.com>
---
kernel/bpf/cgroup.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
index 4355ccb78a9c..b64f6757096c 100644
--- a/kernel/bpf/cgroup.c
+++ b/kernel/bpf/cgroup.c
@@ -965,9 +965,10 @@ static int effective_prog_pos(struct cgroup *cgrp,
init_bstart = bstart;
hlist_for_each_entry(pl, &p->bpf.progs[atype], node) {
- if (!prog_list_prog(pl))
- continue;
-
+ /*
+ * No detaching pl (NULL prog and link) is visible to the callers,
+ * so skip the check compute_effective_progs() needs.
+ */
if (pl->flags & BPF_F_PREORDER) {
if (pl == target_pl)
pos = bstart;
--
2.53.0-Meta
next prev parent reply other threads:[~2026-06-23 17:50 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-23 17:49 [PATCH bpf-next v2 00/15] bpf: A common way to attach struct_ops to a cgroup Amery Hung
2026-06-23 17:49 ` [PATCH bpf-next v2 01/15] bpf: Remove __rcu tagging in st_link->map Amery Hung
2026-06-23 17:49 ` [PATCH bpf-next v2 02/15] bpf: Make struct_ops tasks_rcu grace period optional Amery Hung
2026-06-23 17:49 ` [PATCH bpf-next v2 03/15] bpf: Add bpf_struct_ops accessor helpers Amery Hung
2026-06-23 17:49 ` Amery Hung [this message]
2026-06-23 17:49 ` [PATCH bpf-next v2 05/15] bpf: Replace prog_list_prog() check with direct pl->prog and pl->link check Amery Hung
2026-06-23 17:49 ` [PATCH bpf-next v2 06/15] bpf: Add prog_list_init_item(), prog_list_replace_item(), and prog_list_id() Amery Hung
2026-06-23 17:49 ` [PATCH bpf-next v2 07/15] bpf: Move LSM trampoline unlink into bpf_cgroup_link_auto_detach() Amery Hung
2026-06-23 17:49 ` [PATCH bpf-next v2 08/15] bpf: Add a few bpf_cgroup_array_* helper functions Amery Hung
2026-06-23 17:49 ` [PATCH bpf-next v2 09/15] bpf: Add infrastructure to support attaching struct_ops to cgroups Amery Hung
2026-06-23 17:49 ` [PATCH bpf-next v2 10/15] bpf: Allow all struct_ops to use bpf_dynptr_from_skb() Amery Hung
2026-06-23 17:49 ` [PATCH bpf-next v2 11/15] bpf: tcp: Support selected sock_ops callbacks as struct_ops Amery Hung
2026-06-23 17:50 ` [PATCH bpf-next v2 12/15] bpf: tcp: Support parse/len/write header option hooks in bpf_tcp_ops Amery Hung
2026-06-23 17:50 ` [PATCH bpf-next v2 13/15] libbpf: Support attaching struct_ops to a cgroup Amery Hung
2026-06-23 17:50 ` [PATCH bpf-next v2 14/15] selftests/bpf: Test " Amery Hung
2026-06-23 17:50 ` [PATCH bpf-next v2 15/15] selftests/bpf: Add test for bpf_tcp_ops header option hooks Amery Hung
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