From 2617bbdead6359de809022fea66b28e48784f040 Mon Sep 17 00:00:00 2001 From: Hengqi Chen Date: Wed, 31 Dec 2025 15:19:20 +0800 Subject: [PATCH] LoongArch: BPF: Zero-extend bpf_tail_call() index commit eb71f5c433e1c6dff089b315881dec40a88a7baf upstream. The bpf_tail_call() index should be treated as a u32 value. Let's zero-extend it to avoid calling wrong BPF progs. See similar fixes for x86 [1]) and arm64 ([2]) for more details. [1]: https://github.com/torvalds/linux/commit/90caccdd8cc0215705f18b92771b449b01e2474a [2]: https://github.com/torvalds/linux/commit/16338a9b3ac30740d49f5dfed81bac0ffa53b9c7 Cc: stable@vger.kernel.org Fixes: 5dc615520c4d ("LoongArch: Add BPF JIT support") Signed-off-by: Hengqi Chen Signed-off-by: Huacai Chen Signed-off-by: Greg Kroah-Hartman --- arch/loongarch/net/bpf_jit.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/loongarch/net/bpf_jit.c b/arch/loongarch/net/bpf_jit.c index f97dc99364017..9d9948e549de4 100644 --- a/arch/loongarch/net/bpf_jit.c +++ b/arch/loongarch/net/bpf_jit.c @@ -280,6 +280,8 @@ static int emit_bpf_tail_call(struct jit_ctx *ctx, int insn) * goto out; */ tc_ninsn = insn ? ctx->offset[insn+1] - ctx->offset[insn] : ctx->offset[0]; + emit_zext_32(ctx, a2, true); + off = offsetof(struct bpf_array, map.max_entries); emit_insn(ctx, ldwu, t1, a1, off); /* bgeu $a2, $t1, jmp_offset */ -- 2.47.3