From 9eea8fafe33eb70868f6ace2fc1e17c4ff5539c3 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Thu, 25 Jan 2024 12:55:05 -0800 Subject: [PATCH] libbpf: fix __arg_ctx type enforcement for perf_event programs Adjust PERF_EVENT type enforcement around __arg_ctx to match exactly what kernel is doing. Fixes: 76ec90a996e3 ("libbpf: warn on unexpected __arg_ctx type when rewriting BTF") Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/r/20240125205510.3642094-3-andrii@kernel.org Signed-off-by: Alexei Starovoitov --- tools/lib/bpf/libbpf.c | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 41ab7a21f868..db65ea59a05a 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -33,6 +33,7 @@ #include #include #include +#include #include #include #include @@ -6339,6 +6340,14 @@ static struct { /* all other program types don't have "named" context structs */ }; +/* forward declarations for arch-specific underlying types of bpf_user_pt_regs_t typedef, + * for below __builtin_types_compatible_p() checks; + * with this approach we don't need any extra arch-specific #ifdef guards + */ +struct pt_regs; +struct user_pt_regs; +struct user_regs_struct; + static bool need_func_arg_type_fixup(const struct btf *btf, const struct bpf_program *prog, const char *subprog_name, int arg_idx, int arg_type_id, const char *ctx_name) @@ -6379,11 +6388,21 @@ static bool need_func_arg_type_fixup(const struct btf *btf, const struct bpf_pro /* special cases */ switch (prog->type) { case BPF_PROG_TYPE_KPROBE: - case BPF_PROG_TYPE_PERF_EVENT: /* `struct pt_regs *` is expected, but we need to fix up */ if (btf_is_struct(t) && strcmp(tname, "pt_regs") == 0) return true; break; + case BPF_PROG_TYPE_PERF_EVENT: + if (__builtin_types_compatible_p(bpf_user_pt_regs_t, struct pt_regs) && + btf_is_struct(t) && strcmp(tname, "pt_regs") == 0) + return 0; + if (__builtin_types_compatible_p(bpf_user_pt_regs_t, struct user_pt_regs) && + btf_is_struct(t) && strcmp(tname, "user_pt_regs") == 0) + return 0; + if (__builtin_types_compatible_p(bpf_user_pt_regs_t, struct user_regs_struct) && + btf_is_struct(t) && strcmp(tname, "user_regs_struct") == 0) + return 0; + break; case BPF_PROG_TYPE_RAW_TRACEPOINT: case BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE: /* allow u64* as ctx */