6.6-stable review patch. If anyone has any objections, please let me know.
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From: Andrii Nakryiko andrii@kernel.org
[ 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 andrii@kernel.org Link: https://lore.kernel.org/r/20241009011554.880168-1-andrii@kernel.org Signed-off-by: Alexei Starovoitov ast@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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 834b3e6bc72c3..d39b340222d61 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -3586,7 +3586,7 @@ 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)