6.6-stable review patch. If anyone has any objections, please let me know.
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From: Tao Chen chen.dylane@gmail.com
[ Upstream commit a400d08b3014a4f4e939366bb6fd769b9caff4c9 ]
Referenced commit broke the logic of resetting expected_attach_type to zero for allowed program types if kernel doesn't yet support such field. We do need to overwrite and preserve expected_attach_type for multi-uprobe though, but that can be done explicitly in libbpf_prepare_prog_load().
Fixes: 5902da6d8a52 ("libbpf: Add uprobe multi link support to bpf_program__attach_usdt") Suggested-by: Jiri Olsa jolsa@kernel.org Signed-off-by: Tao Chen chen.dylane@gmail.com Signed-off-by: Andrii Nakryiko andrii@kernel.org Link: https://lore.kernel.org/bpf/20240925153012.212866-1-chen.dylane@gmail.com Signed-off-by: Alexei Starovoitov ast@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- tools/lib/bpf/libbpf.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index ceed16a10285a..834b3e6bc72c3 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -6837,8 +6837,14 @@ static int libbpf_prepare_prog_load(struct bpf_program *prog, opts->prog_flags |= BPF_F_XDP_HAS_FRAGS;
/* special check for usdt to use uprobe_multi link */ - if ((def & SEC_USDT) && kernel_supports(prog->obj, FEAT_UPROBE_MULTI_LINK)) + if ((def & SEC_USDT) && kernel_supports(prog->obj, FEAT_UPROBE_MULTI_LINK)) { + /* for BPF_TRACE_UPROBE_MULTI, user might want to query expected_attach_type + * in prog, and expected_attach_type we set in kernel is from opts, so we + * update both. + */ prog->expected_attach_type = BPF_TRACE_UPROBE_MULTI; + opts->expected_attach_type = BPF_TRACE_UPROBE_MULTI; + }
if ((def & SEC_ATTACH_BTF) && !prog->attach_btf_id) { int btf_obj_fd = 0, btf_type_id = 0, err; @@ -6915,6 +6921,7 @@ static int bpf_object_load_prog(struct bpf_object *obj, struct bpf_program *prog load_attr.attach_btf_id = prog->attach_btf_id; load_attr.kern_version = kern_version; load_attr.prog_ifindex = prog->prog_ifindex; + load_attr.expected_attach_type = prog->expected_attach_type;
/* specify func_info/line_info only if kernel supports them */ btf_fd = bpf_object__btf_fd(obj); @@ -6943,9 +6950,6 @@ static int bpf_object_load_prog(struct bpf_object *obj, struct bpf_program *prog insns_cnt = prog->insns_cnt; }
- /* allow prog_prepare_load_fn to change expected_attach_type */ - load_attr.expected_attach_type = prog->expected_attach_type; - if (obj->gen_loader) { bpf_gen__prog_load(obj->gen_loader, prog->type, prog->name, license, insns, insns_cnt, &load_attr,