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[ Upstream commit3b4d9eb2ee] There is one more problematic case I noticed while recently fixing BPF kallsyms handling incd7455f101("bpf: Fix use after free in subprog's jited symbol removal") and that is bpf_get_prog_name(). If BTF has been attached to the prog, then we may be able to fetch the function signature type id in kallsyms through prog->aux->func_info[prog->aux->func_idx].type_id. However, while the BTF object itself is torn down via RCU callback, the prog's aux->func_info is immediately freed via kvfree(prog->aux->func_info) once the prog's refcount either hit zero or when subprograms were already exposed via kallsyms and we hit the error path added in5482e9a93c("bpf: Fix memleak in aux->func_info and aux->btf"). This violates RCU as well since kallsyms could be walked in parallel where we could access aux->func_info. Hence, defer kvfree() to after RCU grace period. Looking atba64e7d852("bpf: btf: support proper non-jit func info") there is no reason/dependency where we couldn't defer the kvfree(aux->func_info) into the RCU callback. Fixes:5482e9a93c("bpf: Fix memleak in aux->func_info and aux->btf") Fixes:ba64e7d852("bpf: btf: support proper non-jit func info") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Cc: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/875f2906a7c1a0691f2d567b4d8e4ea2739b1e88.1571779205.git.daniel@iogearbox.net Signed-off-by: Sasha Levin <sashal@kernel.org>