Commit 462c124c authored Nov 21, 2018 by Yonghong Song Committed by Daniel Borkmann Nov 21, 2018

bpf: fix a libbpf loader issue



Commit 2993e051 ("tools/bpf: add support to read .BTF.ext sections")
added support to read .BTF.ext sections from an object file, create
and pass prog_btf_fd and func_info to the kernel.

The program btf_fd (prog->btf_fd) is initialized to be -1 to please
zclose so we do not need special handling dur prog close.
Passing -1 to the kernel, however, will cause loading error.
Passing btf_fd 0 to the kernel if prog->btf_fd is invalid
fixed the problem.

Fixes: 2993e051 ("tools/bpf: add support to read .BTF.ext sections")
Reported-by: Andrey Ignatov <rdna@fb.com>
Reported-by: Emre Cantimur <haydum@fb.com>
Tested-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

parent f6161a8f

tools/lib/bpf/libbpf.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -1387,7 +1387,7 @@ 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;
		load_attr.prog_btf_fd = prog->btf_fd;
		load_attr.prog_btf_fd = prog->btf_fd >= 0 ? prog->btf_fd : 0;
		load_attr.func_info = prog->func_info;
		load_attr.func_info_rec_size = prog->func_info_rec_size;
		load_attr.func_info_cnt = func_info_cnt;

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