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authorAndrii Nakryiko <andriin@fb.com>2019-08-01 00:24:05 -0700
committerAlexei Starovoitov <ast@kernel.org>2019-08-01 13:10:45 -0700
commit3415ec643e7bd644b03026efbe2f2b36cbe9b34b (patch)
tree61ba0d59447f209b532a7a5481c202209d75d278 /tools
parent56fbc24116f458a0ea48f9f37fe770fd791042d9 (diff)
libbpf: set BTF FD for prog only when there is supported .BTF.ext data
5d01ab7bac46 ("libbpf: fix erroneous multi-closing of BTF FD") introduced backwards-compatibility issue, manifesting itself as -E2BIG error returned on program load due to unknown non-zero btf_fd attribute value for BPF_PROG_LOAD sys_bpf() sub-command. This patch fixes bug by ensuring that we only ever associate BTF FD with program if there is a BTF.ext data that was successfully loaded into kernel, which automatically means kernel supports func_info/line_info and associated BTF FD for progs (checked and ensured also by BTF sanitization code). Fixes: 5d01ab7bac46 ("libbpf: fix erroneous multi-closing of BTF FD") Reported-by: Andrey Ignatov <rdna@fb.com> Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'tools')
-rw-r--r--tools/lib/bpf/libbpf.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 2e84fa5b8479..2b57d7ea7836 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -2472,7 +2472,11 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt,
load_attr.license = license;
load_attr.kern_version = kern_version;
load_attr.prog_ifindex = prog->prog_ifindex;
- btf_fd = bpf_object__btf_fd(prog->obj);
+ /* if .BTF.ext was loaded, kernel supports associated BTF for prog */
+ if (prog->obj->btf_ext)
+ btf_fd = bpf_object__btf_fd(prog->obj);
+ else
+ btf_fd = -1;
load_attr.prog_btf_fd = btf_fd >= 0 ? btf_fd : 0;
load_attr.func_info = prog->func_info;
load_attr.func_info_rec_size = prog->func_info_rec_size;