From: Stanislav Fomichev <sdf@google.com>
To: bpf@vger.kernel.org
Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org,
martin.lau@linux.dev, song@kernel.org, yhs@fb.com,
john.fastabend@gmail.com, kpsingh@kernel.org, sdf@google.com,
haoluo@google.com, jolsa@kernel.org,
Martin KaFai Lau <kafai@fb.com>
Subject: [PATCH bpf-next v3 1/2] bpf: use proper target btf when exporting attach_btf_obj_id
Date: Thu, 4 Aug 2022 13:11:39 -0700 [thread overview]
Message-ID: <20220804201140.1340684-1-sdf@google.com> (raw)
When attaching to program, the program itself might not be attached
to anything (and, hence, might not have attach_btf), so we can't
unconditionally use 'prog->aux->dst_prog->aux->attach_btf'.
Instead, use bpf_prog_get_target_btf to pick proper target btf:
* when attached to dst_prog, use dst_prog->aux->btf
* when attached to kernel btf, use prog->aux->attach_btf
Fixes: b79c9fc9551b ("bpf: implement BPF_PROG_QUERY for BPF_LSM_CGROUP")
Acked-by: Hao Luo <haoluo@google.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
---
kernel/bpf/syscall.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 83c7136c5788..7dc3f8003631 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -3886,6 +3886,7 @@ static int bpf_prog_get_info_by_fd(struct file *file,
union bpf_attr __user *uattr)
{
struct bpf_prog_info __user *uinfo = u64_to_user_ptr(attr->info.info);
+ struct btf *attach_btf = bpf_prog_get_target_btf(prog);
struct bpf_prog_info info;
u32 info_len = attr->info.info_len;
struct bpf_prog_kstats stats;
@@ -4088,10 +4089,8 @@ static int bpf_prog_get_info_by_fd(struct file *file,
if (prog->aux->btf)
info.btf_id = btf_obj_id(prog->aux->btf);
info.attach_btf_id = prog->aux->attach_btf_id;
- if (prog->aux->attach_btf)
- info.attach_btf_obj_id = btf_obj_id(prog->aux->attach_btf);
- else if (prog->aux->dst_prog)
- info.attach_btf_obj_id = btf_obj_id(prog->aux->dst_prog->aux->attach_btf);
+ if (attach_btf)
+ info.attach_btf_obj_id = btf_obj_id(attach_btf);
ulen = info.nr_func_info;
info.nr_func_info = prog->aux->func_info_cnt;
--
2.37.1.559.g78731f0fdb-goog
next reply other threads:[~2022-08-04 20:11 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-04 20:11 Stanislav Fomichev [this message]
2022-08-04 20:11 ` [PATCH bpf-next v3 2/2] selftests/bpf: Excercise bpf_obj_get_info_by_fd for bpf2bpf Stanislav Fomichev
2022-08-08 14:00 ` [PATCH bpf-next v3 1/2] bpf: use proper target btf when exporting attach_btf_obj_id patchwork-bot+netdevbpf
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