From 10cf6a8968d6edc12e628c4fdc4fd55750c15526 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Tue, 11 Mar 2025 08:51:19 +0900 Subject: [PATCH] libbpf: fix sym_is_subprog() logic for weak global subprogs BugLink: https://bugs.launchpad.net/bugs/2101915 [ Upstream commit 4073213488be542f563eb4b2457ab4cbcfc2b738 ] sym_is_subprog() is incorrectly rejecting relocations against *weak* global subprogs. Fix that by realizing that STB_WEAK is also a global function. While it seems like verifier doesn't support taking an address of non-static subprog right now, it's still best to fix support for it on libbpf side, otherwise users will get a very confusing error during BPF skeleton generation or static linking due to misinterpreted relocation: libbpf: prog 'handle_tp': bad map relo against 'foo' in section '.text' Error: failed to open BPF object file: Relocation failed It's clearly not a map relocation, but is treated and reported as such without this fix. Fixes: 53eddb5e04ac ("libbpf: Support subprog address relocation") Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/r/20241009011554.880168-1-andrii@kernel.org Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin Signed-off-by: Koichiro Den Signed-off-by: Stefan Bader --- tools/lib/bpf/libbpf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index ee820eb00881..9dddcd7451c7 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -3633,7 +3633,7 @@ static bool sym_is_subprog(const Elf64_Sym *sym, int text_shndx) return true; /* global function */ - return bind == STB_GLOBAL && type == STT_FUNC; + return (bind == STB_GLOBAL || bind == STB_WEAK) && type == STT_FUNC; } static int find_extern_btf_id(const struct btf *btf, const char *ext_name)