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libbpf: Fix relocation of kfunc ksym in ld_imm64 insn.
authorAlexei Starovoitov <ast@kernel.org>
Fri, 17 Mar 2023 20:19:18 +0000 (13:19 -0700)
committerAndrii Nakryiko <andrii@kernel.org>
Fri, 17 Mar 2023 22:44:27 +0000 (15:44 -0700)
commit5fc13ad59b60708e52932188854d4d5bf2b0e10e
treeee91e7c2bd0e4a922d7e5a0f98f0886f2c9c8eda
parent58aa2afbb1e61fcf35bfcc819952a3c13d9f9203
libbpf: Fix relocation of kfunc ksym in ld_imm64 insn.

void *p = kfunc; -> generates ld_imm64 insn.
kfunc() -> generates bpf_call insn.

libbpf patches bpf_call insn correctly while only btf_id part of ld_imm64 is
set in the former case. Which means that pointers to kfuncs in modules are not
patched correctly and the verifier rejects load of such programs due to btf_id
being out of range. Fix libbpf to patch ld_imm64 for kfunc.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20230317201920.62030-3-alexei.starovoitov@gmail.com
tools/lib/bpf/libbpf.c